Searching for "invisible colleges" in the Entrepreneurship literature

Faculdade de Economia, Universidade do Porto Master Dissertation in Economics Searching for ‘invisible colleges’ in the Entrepreneurship literature Elsa Maria da Costa Ferreira Supervisor: Aurora A. C. Teixeira September 2009 ii Acknowledgments I would like to thank, first of all, to my supervisor, Professor Aurora Teixeira, for all the support and encouragement she has always given me. Without her, I would not conclude this thesis. Thank you for your friendship and, above all, thank you for believing in me and not letting me quit. You have touched my live in a way I will never forget. To Odília and Rita, a word of gratitude, for the precious help they have given me. A word of acknowledgment to my colleagues at FCNAUP for their help and words of motivation. To Dra. Meibel and Professora Maria Daniel, thank you for allowing me to seize this opportunity. To D. Dorinda, Carlos and Anita, a word of profound gratitude for their support and friendship. I could not have better colleagues. To all my friends, thank you for your understanding and precious support. I promise I will never miss another dinner from now on. To Mafalda, I will never thank enough. All the weekends spent in FEP, all the hours we put into to this task…I could not have done it without you…together, all the way, my friend. Finally, we want to thank my family for their support, specially my beloved parents, for never loosing their faith in me and stick by my side not matter what. iii Abstract The explosion of entrepreneurship scholarship aroused the need to measure scientific production (namely through bibliometric and scientometric approaches) in the field and to understand the scientific structure of this same field. Underlying the scientific structure of a field is the network of informal communicational linkages established between the most influential scholars within that area. These groups of mutually interacting and prolific scientists that exchange knowledge through communication channels are named “invisible colleges”. In spite of the (increasing) academic interest on entrepreneurship subjects and area, invisible colleges, per se, have not been thoroughly investigated. Thus, in the present study we performed a two staged analysis to discover if there are invisible colleges in the field of entrepreneurship. First, we conduct a bibliometric analysis on three “seed” journals of the field: Entrepreneurship Theory and Practice (ETP); Journal of Business Venturing (JBV) and Small Business Economics (SBE). Resorting to the citation bibliometric technique we identify the most cited authors, studies and journals of each “seed” journal and characterize their intellectual scientific structure. Second, we executed a comprehensive analysis on the most influential authors, based on their professional affiliation and educational training, in order to map the informal links between the most cited authors. Empirical evidence confirms the existence of two invisible colleges in entrepreneurship research: one, directed to broad entrepreneurship issues and associated with ETP and JBV, and the other, economic-oriented and related with JBV. Specifically, results show that ETP and JBV have similar intellectual bases, associated with the research area targeting specially to entrepreneurship, while SBE differs from the other two journals and gives emphasis to more economic-oriented research. We further uncover that the most influential authors in the field are highly connected with each other. Keywords: Invisible College; Entrepreneurship; Bibliometrics iv Contents Acknowledgments ..................................................................................................................ii Abstract .............................................................................................................................iii Contents .............................................................................................................................iv List of Tables.........................................................................................................................vi List of Tables – Appendix .....................................................................................................vi List of Figures.......................................................................................................................vii Introduction ............................................................................................................................1 Chapter 1. Searching for Invisible Colleges in entrepreneurship scientific research: a literature review....................................................................................................3 1.1. Initial considerations....................................................................................................3 1.2. Bibliometrics and Scientometrics: concept and main applications .............................3 1.3. The concept of “invisible colleges” and the scope for its application in the scientific area of entrepreneurship ..............................................................................................13 Chapter 2. Searching for the ‘invisible colleges’ in the Entrepreneurship literature: methodological underpins ..................................................................................20 2.1. Initial considerations..................................................................................................20 2.2. A brief description of the selected ‘seed journals’ – Entrepreneurship Theory and Practice, Journal of Business Venturing, Small Business Economics ........................20 2.3. Data gathering considerations ...................................................................................26 Chapter 3. Searching for the ‘invisible colleges’ in the Entrepreneurship literature: empirical results..................................................................................................31 3.1. Initial considerations..................................................................................................31 3.2. Who are the most cited authors, studies and journals in the last decades?................31 v 3.3. Are there any similarities/correlations between the most cited authors regarding their educational training and professional affiliation, and research area?..........................41 3.4. Are there different “invisible colleges” in entrepreneurship research area? .............47 Conclusions ..........................................................................................................................51 References ............................................................................................................................53 Appendix ............................................................................................................................61 vi List of Tables Table 1: Bibliometric studies – Journal analysis....................................................................7 Table 2: Bibliometric studies – Themes categorizations........................................................9 Table 3: Bibliometric studies – Research Intellectual Structures.........................................12 Table 4: Bibliometric studies – Research Invisible Colleges...............................................16 Table 5: Description, scope, year first published, impact factor and present editor of ETP, JBV and SBE.........................................................................................................22 Table 6: List of the top 20 most productive authors in ETP, JBV and SBE ........................25 Table 7: Distribution of articles and citations per journals and year from 1992 to 2008.....28 Table 8: Ranking of the Top 20 most cited authors in ETP, JBV and SBE (name and number of citations)...............................................................................................32 Table 9: Areas of scientific research associated with top cited authors ...............................33 Table 10: Ranking of the Top 10 most cited studies in ETP, JBV and SBE........................37 Table 11: Ranking of the Top 20 most cited journals in ETP, JBV and SBE......................39 Table 12: Information on the affiliation, educational background and research area of the 47 most cited authors..................................................................................................42 List of Tables – Appendix Table A 1: John Carroll University Classification of entrepreneurship journals .................61 Table A 2: Ranking of the Top 10 most cited articles in Entrepreneurship Theory and Practice ...............................................................................................................62 Table A 3: Ranking of the Top 10 most cited articles in Journal of Business Venturing....63 Table A 4: Ranking of the Top 10 most cited articles in Small Business Economics .........64 Table A 5: Information on current and previous affiliations/ visiting academic institutions ............................................................................................................................65 vii List of Figures Figure 1: Conceptual model for analysing the structure of an invisible college in entrepreneurship ....................................................................................................19 Figure 2: Evolution of the number of articles per year published in ETP, JBV and SBE, 1976-2008..............................................................................................................23 Figure 3: Methodological scheme ........................................................................................29 Figure 4: Mapping the international scientific linkages of the most influential authors in entrepreneurship by ‘seed journal’ ........................................................................34 Figure 5: Mapping links among top cited authors in entrepreneurship scientific area ........46 1 Introduction Academic research on entrepreneurship has increased over the last few decades, accompanying society’s interest on the subject (Landström, 2005). In fact, entrepreneurship research and teaching has been one of the most prominent social sciences in recent years, with jobs with a focus on entrepreneurship and faculty expertise in entrepreneurship continuing to increase (Finkle, 2007). The explosion of entrepreneurship scholarship aroused the need to measure scientific production (namely through bibliometric and scientometric approaches) in entrepreneurship and understand the scientific structure of the field, so that several studies have been devoted to that issue (Cornelius et al., 2006, Grégoire et., 2006, Schildt et al., 2006). Underlying the scientific structure of a field is the network of informal communicational linkages established between the most influential scholars within that area. These groups of mutually interacting and prolific scientists that exchange knowledge through communication channels were named “invisible colleges” (Crane, 1972) and are the aim of our study. In spite of the academic interest on entrepreneurship, we found that invisible colleges, per se, have not been thoroughly investigated (exception maid to the work of Reader and Watkins in 2006). Thus, the purpose of the present study is to fill this gap in entrepreneurship research literature and assess for the existence of invisible colleges within the entrepreneurship field, following the research framework proposed by Zuccala (2006). According to the methodology, invisible colleges are generated by the intersection of three key elements: social actors (influential authors); subject specialty (research areas) and information use environment (professional affiliation), underpinned by the exchange of (formal and informal) communication. In a first stage, we undertake a bibliometric/ scientometric approach, more specifically, we perform a (co)citation analysis, based on data collected from three “seed” journals in entrepreneurship research: Entrepreneurship Theory and Practice (ETP); Journal of Business Venturing (JBV) and Small Business Economics (SBE). We gather evidence about the most cited authors, studies (articles or books) and journals for each of the “seed” journals, which allow us to characterize the intellectual bases of entrepreneurship, comparing the results for each of the selected journal. 2 In a second stage, we confirm the existence of linkages between the most influential (i.e. most cited) authors, though a comprehensive study of their affiliations, educational training and research areas. Examining the social ties (or links) that connect influential authors from entrepreneurship field is fundamental to comprehend the multi-faceted nature of the invisible colleges, since these are based on (formal and informal) exchange of scientific knowledge. The combination of evidence from the first and second stages of the work give us empirical support to conclude about the existence of invisible colleges. Synthesizing, the present study seeks to investigate three research issues: 1) identify the most cited authors, studies (article or book), and journals, in each of the entrepreneurship journals selected; 2) explore the linkages between the most cited authors through an analysis of their educational background, research area and profession affiliation and 3) infer the presence of invisible colleges in the entrepreneurship scientific field. The study is structured as follows. In Chapter 1 we review the literature related to bibliometric and scientometric methods, illustrating with examples, their main applications in entrepreneurship and other scientific areas. Moreover, the concept of invisible college is defined along with Zuccala’s approach to the theme. Chapter 2 is devoted to the description of data and methodological considerations. Next, in Chapter 3, we analyse the most cited authors, studies and journals of each “seed” journal and perform a comprehensive study on the linkages between the most cited authors. Finally, we draw the main conclusions, pointing the limitations of the study and suggesting paths for future research. 9 Table 2: Bibliometric studies – Themes categorizations Application Areas Scientific Areas Authors (Date) Main Research Items Main Results - Structural Change Silva and Teixeira (2008) Objectives: - Provide a comprehensive survey of the economic literature on structural change Bibliometric Indicators: - Number of citations; Number of articles - Co-authoring; Abstracts analysis; Keyword analysis - Technological issues increased there relevance during the studied period - Recent trends reflect a rising interest towards empirical work, despite the increased relevance of formal work in the nineties - Evolutionary Economics Silva and Teixeira (2009) Objectives: - Explore main research paths and contributions in the field of evolutionary economics Bibliometric Indicators: - Number of citations; Number of articles; Abstracts analysis; Keyword analysis - Evolutionary contributions don’t converge to an integrated approach - Arising of two extreme strands: “History of Economic Though and Methodology” and “Games” - Increase of formal approaches in contrast with the stagnation of empirical work - Regional studies Cruz and Teixeira (Forthcoming) Objectives: - Provide evidence that empirically complements the qualitative surveys of cluster-related literature Bibliometric Indicators: - Number of citations; Number of articles; Co-authoring - Abstracts analysis - Share of “Appreciative+Empirical” and “Formal+Empirical” articles published in the top ranked cluster-related journals are above the average - Evidence of positive correlation between the “quality” of the journals and formal related research Van Praag and Versloot (2008) Objectives: - Assess the contribution of entrepreneurs to the economy comparatively to non-entrepreneurs Bibliometric Indicators. - Keyword analysis - Title, abstract and full-text analysis - Entrepreneurs have a higher, but more volatile, contribution to employment generation. They pay lower wages, but, their employees appear to be more satisfied - Entrepreneurs contribute equally importantly to innovation but trough different aspects - Entrepreneurs do not have higher productivity levels than their counterparts. They contribute more than their counterparts to growth of value added and productivity - Despite having lower and riskier incomes, entrepreneurs are more satisfied Watkins and Reader (2004) Objectives: - Identify current trends in entrepreneurship research, in 2000 and 2001 Bibliometric Indicators: - Textual analysis (keyword and abstract analysis); Cooccurrence matrix - Identification of twenty two clusters - Incidence of work in areas very attended in the past or in vogue in the present, such as, respectively, Entrepreneurial Psychology and Social Entrepreneurs or Networking among Female Entrepreneurs was lower than expected Themes categorization - Entrepreneurship Ratnatunga and Romano (1997) Objectives: - Analyze, with a quantitative and qualitative approach, the articles in contemporary small enterprise research Bibliometric Indicators: - Number of citations; Number of articles - Articles full-text analysis - Increase percentage of most cited articles, published by the source journals - Substantial percentage of articles (more than 50%) are well based in observational and contemplative theory - Diversity of topic areas empirical support that there is no coherent structure to research in the field 10 literature, that gave a more accurate and complete insight of the evolution of regional literature and paths to follow in this scientific area. Another example of a bibliometric analysis of contents, this time applied to entrepreneurship, is the review of 57 studies performed by Van Praag and Versloot (2008) with the purpose of measuring the contribution of entrepreneurs to the economy in comparison to non-entrepreneurs, in terms of employment generation and dynamics, innovation, productivity and growth and individuals’ utility levels. The authors conducted a thoroughly research of title, abstract and fulltext, in order to discover if recent empirical evidence could substantiate the common notion that entrepreneurs are beneficial to the economy. Watkins and Reader (2004) employed an original approach to identify the current trends in the entrepreneurship field, in 2000 and 2001. The authors resort to a textual analysis and the ARPENT corpus as a data source, which allowed them to obtain a better understanding of the major themes in the literature. The data results from a collection of abstracts from 13 entrepreneurship niche journals included in the ARPENT corpus. By doing so, the authors expect to overcome some limitations such as the delay associated to the use of citation tools; the biased towards journals of North American origin and limited coverage related to the use of the Social Sciences Citation Index. Watkins and Reader (2004) conclude that the textual analysis software provides clusters by sets of keywords that seem to meet the expectations of entrepreneurship researchers, with the advantages of having more data available and clusters’ generation consume less time. Ratnatunga and Romano (1997) complemented their 1996 study with a qualitative categorization of the topic, methodology and objectives of the most cited articles, to identify the intellectual origins and directions of entrepreneurship research. With respect to researching the intellectual structures (Table 3), in the sub-field of innovation, Cottrill et al. (1989) investigate the structure of the discipline, through a co-citation analysis, exploring the interrelationships between the interdisciplinary specialties of the diffusion of innovations and technology transfer. Samples were drowned from Social Sciences Citation Index, concerning the 1966-1972 period of study. The authors discover five major clusters, closely related. Nerur et al. (2008) also used a co-citations analysis to study the evolution of the intellectual structure of the strategic management field. The authors aim at discovering the subfields (and the relationships between them) that constitute the intellectual structure of the 11 discipline, identifying the influential authors in the field and graphically mapping the results. In field of management information systems, Culnan (1987) updated a previous work, dated from 1986, and assessed the intellectual development of the scientific area, through a co-citation analysis. The study provided evidence of the discipline’s progress toward a cumulative research tradition. In entrepreneurship research, an, Cornelius et al. (2006) performed a bibliometric analysis of cited articles, at three points in time, 1986-1990, 1993-1997 and 2000-2004, in order to examine the intellectual structure of the field and assess its the stage of maturation. The data is provide by the Social Sciences Citation Index, through a research of academic articles that include the word “entrep*” in the title, key words, or abstract between 1986 and February, 2005. The idea is to determine the research front of the field, perceiving the most influential scholars and discovering the linkages between them and other authors. By evaluating the research output of key authors and the research themes over time, the authors find evidence to support the idea that entrepreneurship is evolving into a mature field. Similar to the previous work purpose, Grégoire et al. (2006) studied the intellectual bases of entrepreneurship to understand the extent and nature of conceptual convergence in entrepreneurship research. In the study, they analyze the co-citation networks provided by the articles published between 1981 and 2004 in the Frontiers of Entrepreneurship series and complemented it with an analysis by period (1981-1986, 1987-1992, 1993-1998 and 1999-2004). The emergence of consistent networks of co-citation provide evidence to support the argument that there has been convergence in entrepreneurship research over the last twenty five years, although the overall levels of convergence observed were relatively low. Schildt et al. (2006) conducted a bibliometric study and analyzed co-citations patterns of entrepreneurship-related articles, published during the period of 2000 to 2004. The data collection was initially based in a research of articles with words beginning with “entrep*” in their abstract, title, or keywords from the Social Sciences Citation Index published during the studied period and then, the study was narrowed to thirty journals that contain entrepreneurshiprelated articles. By mapping the structure of entrepreneurship literature, the authors seek to obtain some evidence regarding the research directions of the subject, clarifying the state of entrepreneurship field as a discipline and fulfilling a literature gap. 12 Table 3: Bibliometric studies – Research Intellectual Structures Application Areas Scientific Areas Authors (Date) Main Research Items Main Results - Innovation Cottrill et al. (1989) Objectives: - Explore the interrelationships between the specialties of the diffusion of innovations and technology transfer, in the 1966-1972 period Bibliometric Indicators: - Number of citations; Number of articles; Co-citation analysis; Cluster and factor analysis; Multidimensional scaling - Clusters of authors obtained are similar to those identified in major reviews of the innovation literature - Little cross-referencing between the diffusion of innovations and the technology transfer authors - Technology transfer research tradition is less integrated than the diffusion of innovations tradition - Strategic Management Nerur et al. (2008) Objectives: - Trace the evolution of the intellectual structure of the strategic management field during the period 1980–2000 Bibliometric Indicators: - Number of citations; Number of articles; Co-citation analysis; Multidimensional scaling; Factor analysis; Pathfinder analysis - Multidisciplinary origins of strategy - Large number of significant inter-correlation between factors suggests that the field did not become fragmented - Theories of the firm have become central to strategy research, which suggests a greater theoretical orientation - Management Information Systems Culnan (1987) Objectives: - Document the intellectual structure of Management Information Systems, from 1980 to 1985 Bibliometric Indicators: - Number of citations; Number of articles; Co-citation analysis - Identification of five clusters: foundations; psychological approaches to MIS design and use; MIS management; organizational approaches to MIS design and use; and curriculum Cornelius et al. (2006) Objectives: - Analyze the development of entrepreneurship with respect to the research front and knowledge base, during the periods of 1986-1990, 1993-1997 and 2000-2004 Bibliometric Indicators: - Number of citations; Number of articles; Co-citation analysis; Cluster analysis - Entrepreneurship research has been increasing self-reflective - The number and influence of outsiders has decreased steadily over time while the reliance on insiders is greater - Theoretical issues are more pervasive - Research interests have evolve, despite their consistency - Researchers have increasingly specialized thematically Grégoire et al. (2006) Objectives: - Assess conceptual convergence of entrepreneurship field, through network co-citation analysis Bibliometric Indicators: - Number of citations; Number of articles; Co-citation analysis; Cluster analysis - Evidence of convergence in entrepreneurship research over the last twenty five years - Levels of convergence comparatively low - Entrepreneurship research bases on the contributes of other disciplines, but evidence indicates that the field relies increasingly on its own literature Schildt et al. (2006) Objectives: - Analyze co-citation patterns of entrepreneurship-related articles published, from 2000 to 2004 Bibliometric Indicators: - Number of citations; Number of articles; Co-citation analysis; Jaccard index; Cluster algorithm - Evidence of fragmentation in entrepreneurship research - Research findings appear to be noncumulative - Research mostly centred on the United States, but other countries contribute significantly - Signs of isolation among the entrepreneurship scholars Research Intellectual Structures - Entrepreneurship Etemad and Lee (2003) Objectives: - Define the knowledge network associated with the field of international entrepreneurship, during the period of 1992 to 2000 Bibliometric Indicators: - Number of citations; Number of publications; Bolean search progression of key words; Co-authoring; Authors’ affiliations analysis - Scholarly articles, followed by book reviews dominate the document types - Upward movement over time in both the number of articles and their associated citations - Mild upward trend in both size of scholarly teams and theirs co-authorship, during the period of 1992-1998 - Authors affiliated with institutions located in the U. S. dominate the distribution, but other country affiliations are also reported - Scholarly articles and books constitute the most important sources upon which research relay 13 Twenty five major research trends were identified; being presented the ten most cited groups of study and subsequently explored their interrelatedness, through a co-citation network. 7 Etemad and Lee (2003) studied the knowledge network of the sub-field of international entrepreneurship, during the period of 1992 to 2000, through a Boolean progression of key words that focussed on Social Sciences Citation Index’s available database. By using a bibliometric methodology, namely citation analysis, they expected to reveal the antecedents of an emerging field and discover the unique characteristics of its knowledge network. The results obtained confirm Etemad and Lee’s (2003) initial hypothesis: scholars of international entrepreneurship depend highly on the disciplines of international business and entrepreneurship to support their scientific research. Bibliometric methodology is also employed in the investigation of possible (formal and informal) linkages between researchers, which have been identified as Invisible Colleges. The following section explains, in detail, the concept of Invisible Colleges and provides examples of their application in entrepreneurship and other scientific areas. 1.3. The concept of “invisible colleges” and the scope for its application in the scientific area of entrepreneurship The term “invisible colleges” was introduced in 1645 by Robert Boyle (Wallace, 2007), when the Royal Society of London was founded, as a form of describing the fact that its members, although lacking a formal institution or college, were geographically close and shared common scientific interests (Lievrouw, 1989; Zuccala, 2006). Price (1961; 1963) recover the terminology and applied it to the existence of informal communication network between scholars from several institutions, often geographically separated from one another. The invisible college was defined as a hierarchical and elitist group of scholars, supported by an expectable inequality and a highly connection (Price, 1971). Crane (1972) undertook, influenced by Price’s work, a comprehensive examination of the invisible college phenomenon (Wallace, 2007). Focussing on communication among 7 The ten most cited groups identified were: Entrepreneurial Networks and Resource Accumulation; Corporate Entrepreneurship and Venturing; Conceptualizations of Entrepreneurial Processes; Value Creation from Corporate Entrepreneurship; Alertness, Opportunity Creation, and Creative Destruction; Psychological Characteristics of Entrepreneurs, Qualitative Research Methods; Entrepreneurial Firm Survival and Growth; Societal Consequences of Entrepreneurship and Born-Global Firms (Schildt et al., 2006). 14 scientists, the author expanded the scope of the concept of informal communication, including informal discussions, relationships between teachers and students, during a thesis preparation, and a scientist’s work influence on another. The study consisted in an analysis of the growth of communication relations between sociologists and mathematicians, sustained by the collection of survey data on co-authorship patterns and exchange of preprints (Zuccala, 2006). Despite Crane’s major scientific contribution, Lievrouw (1989) points some limitations to the work, particularly with respect to the definition of invisible college and the lack of real information about informal communication. According to Lievrouw (1989), several other studies (e.g. Crawford, 1971; Mullins, 1968; Lingwood, 1969; Chubin, 1976) reveal the same difficulty with the definition of the concept and its operationalization. This problem is common in the social studies of science, reflecting the use of products of science (for instance, published documents) to capture social processes of science, which have a communicative nature. To Lievrouw (1989: 622), it is a paradox that “the term invisible college describes an informal communication process, yet researchers look for it in formal social structures and documents” and explains an invisible college as “a set of informal communication relations among scientists or other scholars who share a specific common interest or goal”. Zuccala (2006: 155) emphasis the need to understand the multi-faceted nature of the invisible college, proposing the following definition: An invisible college is a set of interacting scholars or scientists who share similar research interests concerning a subject specialty, who often produce publications relevant to this subject and who communicate both formally and informally with one another to work towards important goals in the subject, even though they may belong to geographically distant research affiliates. The novelty in the definition, as Zuccala (2006) points, is its openness to the possibility of combining different types of analysis – bibliometric, sociometric and qualitative – in the study of invisible colleges, benefiting from their unique contributions. Bibliometric methodology, nevertheless, remains a fundamental tool to researchers by providing a concrete representation of the relationships among the products of science and enabling documents mapping, generated by communication acts (Lievrouw, 1989). Co-citation analysis 8 has developed into the principal bibliometric technique used to explore the intellectual structure of scientific communication, leaning on citations and co-citations 8 See Small (1973) to a better understanding of the concept “co-citation analysis”. 15 (Lievrouw, 1989; Bayer et al., 1990; Gmür, 2003). According to Bellardo (1980: 231) cocitation analysis is founded on the premise that “the greater the number of times that a pair of documents are cited together, the more likely it is that they are related in content”. A cocitation occurs when two references or authors are mentioned in the same bibliography and serves as a measurement for the closeness of content (Small, 1973; Garfield, 1978; Gmür, 2003). Although there has been some criticism regarding the use of citation and co-citation analysis, as the utilization of citation links is considered an inadequate representation of communication among researchers (Lievrouw, 1989), their credibility as indicators of scientific communication was vouch for by authors such as Small (1978) and Garfield (1979) and they constitute the grounding for the identification of invisible colleges (Gmür, 2003). Thus, the research of invisible colleges is one of the main applications of bibliometrics (cf., Table 4). In the field of economics, namely Industrial Relations and Labour, Casey and McMillan (2008) and McMillan and Casey (2007) assessed the intellectual bases of the area over a reasonable span of years (1974-2006) based on the analysis of one single journal, respectively, Industrial & Labor Relations Review and British Journal of Industrial Relations. These studies, according to the authors, aim at identifying the invisible colleges of the respective journals, through a co-citation analysis. The invisible colleges are defined as research networks that refer to each other in their documents without being linked by formal organizational ties. However, the empirical application performed by the authors seems to be rather distant of their theoretical concept of invisible colleges, since co-citation analysis is based on formal links. In fact, both the studies defined invisible colleges as social processes, based on informal links, but, empirically, invisible colleges are treated as structures of scholarship, measured by formal elements such as published documents. Also within economics, but regarding the sub-field of Technology and Innovation, Verspagen and Werker (2004) analysed the structure of collaboration and interaction between researchers, applying a survey methodology that allowed them to map the intellectual relations between active contributors in the discipline and identified possible social networks, i.e., invisible colleges. 16 Table 4: Bibliometric studies – Research Invisible Colleges Application Areas Scientific Areas Authors (Date) Main Research Items Main Results Casey and McMillan (2008) Objectives: - Compare Industrial & Labor Relations Review intellectual bases across three periods: 1974-1984, 1985-1995 and 1996-2006 Bibliometric Indicators: - Number of citations; Number of articles; Co-citation network analysis - The most cited journals were economic-oriented during the studied period - Emergence of the field of human resource and management in recent years - Industrial Relations & Labor McMillan and Casey (2007) Objectives: - Uncover British Journal of Industrial Relations for two time periods, 19861995 and 1996-2005 Bibliometric Indicators: - Number of citations; Number of articles; Co-citation network analysis - Evidence suggests that economics literature remains important, but sociological and management literature has dominated in recent years - Regarding authors, Millward’s initial influence has been replaced by Kelly and Wood - Possible signs of internationalization - Management McMillan (2008) Objectives: - Examine R&D Management, in four time periods, 1986-1990, 1991-1995, 1996-2000 and 2001-2005 Bibliometric Indicators: - Number of citations; Number of articles; co-citation network analysis - During the two first periods R&D Management focus on more traditional technology and innovation management sources, contrasting with the last two periods, in which R&D Management was based on journals more detached of the traditional sources - Cohen and Levinthal’s absorptive capacity model dominates the final two periods and possibly constitutes an emerging base - Economics of Technology and Innovation Verspagen and Werker (2004) Objectives: - Identify the role of “intellectual leaders” in connecting the research network - Study the structure of the field in terms of sub-communities Bibliometric Indicators: - Survey analysis - The network of scholars in the field may be characterized as a scale-free network - The field does not seem to evolve in a mode of competition between paradigmatic approaches to the object of study Research Invisible Colleges - Entrepreneurship Reader and Watkins (2006) Objectives: - Identify groups of entrepreneurship authors whose work falls into similar areas and explore the themes that characterize entrepreneurship field - Investigate the social and collaborative structure of entrepreneurship research Bibliometric Indicators: - Number of citations; Number of articles; Co-citation analysis; Cluster analysis; Correlation matrix; Factor analysis; Questionnaire survey - Findings reveal nine clusters of authors whose work falls into similar areas - Little evidence of international sharing of ideas - Strong evidence that closely related authors share both formal and informal communication links 17 In the field of management, McMillan (2008) presents a co-citation analysis of R&D Management, for four time periods, 1986-1990, 1991-1995, 1996-2000 and 2001-2005, with the purpose of assessing possible changes in its intellectual base, identified by the author, albeit in a simplistic way, as ‘invisible colleges’. The motivation behind the work is the opportunity to fulfil a literature gap, conducting a comprehensive analysis of the journal, and providing some directions to future research. In entrepreneurship scientific area, Reader and Watkins (2006) explored the existence of invisible colleges, by complementing a co-citation analysis of the field’s scientific structure with a questionnaire survey. The authors resort to a comprehensive database, created by the Southampton Business School, which includes full coverage of the major niche journals in entrepreneurship, conference proceedings and other major, but not so specific, journals as those on the Social Sciences Citation Index. The key authors were defined through a process of crossreferencing that reduced a list of 4405 documents initially generated by a keyword search of the word “Entrepreneur$” within the database. Using the author co-citation and factor analysis, the authors try to identify, respectively, groups of entrepreneurship scholars whose work falls into similar areas and the themes that characterize and define the field. The survey allowed them to explore the social and collaborative nature of entrepreneurship research between the leading co-cited authors, unveiled in the first stage of the work. Therefore, the subfields identified in the author co-citation analysis of informal communication links between closely related authors and then validated by the survey represent to Reader and Watkins (2006) the “invisible colleges”. In spite of all the research devoted to assess the intellectual structure of the entrepreneurship field, namely the presence and nature of the scholar communities that comprise the field, there is steel very little literature specifically focussed on the subject of invisible colleges. The multi-faceted constitution of this phenomenon, particularly the issue structure versus social process, requires, as Lievrouw (1990) recommended, distinct approaches to the subject in order to provide new insights on the discipline. Therefore, the aim of this work is to explore the existence of invisible colleges in the field of entrepreneurship, undertaking a citation analysis of the articles published in three “seed journals” within the entrepreneurship area – Entrepreneurship Theory and Practice; Journal 18 Business Venturing and Small Business Economics. For that purpose we resort to the methodology proposed by Zuccalla (2006) in order to operationalise the (widely debatable) concept of ‘invisible college’. We argue that although this theory underlying the concept is well developed and relatively consensual the empirical application or the operationalisation of such a concept lags well behind the theoretical achievements. Moreover, in our view, one need an objective framework structure which enables, in a more rigorous manner to approach the ‘measurement’ and ‘assessment’ of invisible colleges. To the best of our knowledge such operationalisation of the Invisible College concept has never been applied in entrepreneurship literature. According to Zuccala’s (2006) previous mentioned definition of Invisible Colleges and its research framework, the invisible college is a consequence of the interrelationship (through formal and informal communication) between three key elements: the subject specialty, the social actors and Information Use Environment. The first informs the invisible college of its disciplinary rules and research problems, the second refers to the scientific scholars who understand and agree upon the rules and interact one another to solve problems and the third and last element, represents the scientific workspace, i.e., the “set of elements that affect the flow and use of information messages into, within, and out of any definable entity” (Taylor, 1986: 3). The social actors, i.e., the most influential authors resort to the invisible college to support their search of information and sharing patterns (informal communication) and reinforce the invisible college through bibliometric artifacts (formal communication). Therefore, Zuccala (2006: 8) concludes that the invisible college is an organizational structure produced by “the space that intersects the Information Use Environment, the subject specialty and the social actors” (cf., Figure 1). Thus, similarly to previous studies (e.g. McMillan, 2008; Casey and McMillan, 2008; McMillan and Casey, 2007), the present work applies a bibliometric analysis in order to obtain empirical evidence that allows to asses the development of the field’s intellectual bases. However, unlike these studies that are constrained to a narrow definition of invisible colleges and do not provide any insights regarding scholars interrelatedness through informal channels, we complement the study of the most cited authors, articles/books and journals, with an analysis of the linkages between the most influential (i.e., most cited) authors, based on their educational training affiliation, professional affiliation and research area. 25 Table 6: List of the top 20 most productive authors in ETP, JBV and SBE Rank Number of Articles Author Affiliation ETP JBV SBE ETP JBV SBE Total Chrisman, J.J. Mississippi State University, US 1 7 - 31 10 0 41 Gartner, W.B. Clemson University, US 4 3 40 15 16 3 34 Wright, M. University of Nottingham, UK 3 9 7 16 9 9 34 Zahra, S.A. University of Minnesota, US 2 5 177 17 13 1 31 Shepherd, D.A. Indiana University, US 8 2 - 11 17 0 28 Macmillan, I.C. University of Pennsylvania, US - 1 - 0 25 0 25 Thurik, A.R. Erasmus University Rotterdam, NL 128 92 1 2 2 20 24 Mcdougall, P.P. Indiana University, US 9 10 69 11 9 2 22 Acs, Z.J. George Mason University, US - - 2 0 0 19 19 Sapienza, H.J. University of Minnesota, US 11 12 178 10 8 1 19 Westhead, P. University of Durham, UK 33 17 19 6 7 6 19 Birley, S. Bae Sistems (Retired), UK 26 6 - 7 11 0 18 Chua, J.H. University of Calgary, CA 6 30 - 13 5 0 18 Audretsch, D.B. Max Planck Institute of Economics, DE 78 61 4 3 3 11 17 Katz, J.A. Saint Louis University, US 10 42 70 11 4 2 17 Brush, C. Babson College, US 16 22 179 9 6 1 16 Kuratko, D.F. Indiana University, US 5 203 - 15 1 0 16 Covin, J.G. Indiana University, US 12 31 - 10 5 0 15 Reynolds, P.D. George Mason University, US 299 32 8 1 5 9 15 Shane, S. Case Western Reserve University, US 300 4 - 1 14 0 15 Busenitz, L. University of Oklahoma, US 20 23 - 8 6 0 14 Hisrich, R. Thunderbird School of Global Management, US 36 13 180 5 8 1 14 Hoy, F. University of Texas at El Paso, US 13 43 - 10 4 0 14 Cooper, A.C. Purdue University (Retired), US 79 8 - 3 10 0 13 Winn, J. University of Denver, US 7 - - 13 0 0 13 Honig-Haftel, S. Wichita State University, US (Retired) 129 62 14 2 3 7 12 Storey, D.J. University of Warwick, UK - - 3 0 0 12 12 Wiklund, J. Syracuse University, US 17 93 181 9 2 1 12 Bruton, G. Texas Christian University, US 21 63 - 8 3 0 11 Cowling, M. Institute for Employment Studies, UK 301 - 5 1 0 10 11 Deeds, D. University of St. Thomas, US 80 14 - 3 8 0 11 Gatewood, E.J. Wake Forest University, US 22 94 182 8 2 1 11 Reid, G.C. University of St Andrews, UK 302 - 6 1 0 10 11 Sharma, P. Family Firm Institute, Inc., US 18 95 - 9 2 0 11 Steier, L. University of Alberta, CA 23 65 - 8 3 0 11 De Cenzo, D.A. Coastal Carolina University, US 14 - - 10 0 0 10 Franklin, C.M. † University of Southern California, US 15 - - 10 0 0 10 Oviatt, B. University of New South Wales, AU 24 96 - 8 2 0 10 Phan, P.H. Johns Hopkins University, US - 11 183 0 9 1 10 van Stel, A. EIM Business and Policy Research, NL 303 205 11 1 1 8 10 Baron, R.A. Oklahoma State University, US 130 18 - 2 7 0 9 Bird, B. American University, US 19 - - 9 0 0 9 Carree, M. Maastricht University, NL - 206 12 0 1 8 9 26 (…) Rank Number of Articles Author Affiliation ETP JBV SBE ETP JBV SBE Total Cressy, R. University of Birmingham, UK - - 10 - - 9 9 Kellermanns, F.W. Mississippi State University, US 25 207 - 8 1 - 9 Wagner, J. University of Lueneburg, DE - - 9 - - 9 9 Abetti, P.A. Rensselaer Polytechnic Institute, US - 15 - - 8 - 8 Autio, E. Imperial College London, UK - 208 15 - 1 7 8 Fitzroy, F.R. University of St Andrews, UK - - 13 - - 8 8 Kaufmann, P.J. Boston University, US 305 19 - 1 7 - 8 Venkataraman, S. University of Virginia, US - 16 - - 8 - 8 Dant, R.P. University of Oklahoma, US - 20 - - 7 - 7 Henrekson, M. Research Institute of Industrial Economics, SE - - 16 - - 7 7 Johnson, P. Durham University, UK 308 - 20 1 - 6 7 Karlsson, C. Jönköping University, SE - - 17 - - 7 7 Levesque, M. University of Waterloo, CA - 21 - - 7 - 7 Watson, R. University of Durham, UK - - 18 - - 7 7 Source: Authors computations based on our sample of citations in ETP, JBV and SBE collected manually for ETP and from Social Sciences Citation Index (SSCI) of the ISI Web of Science, for JBV and SBE 12 . Note: Since the affiliation of the authors could be changed in the future, the validity of data concerning current affiliation is only guaranteed until August of 2009. Extending the analysis to the country where the institutions affiliated with the leading contributors are located, United States of America clearly stands out as the major provider of the most prolific authors, with a total of thirty four leading authors, followed by the United Kingdom with twelve contributors. This result, however, differs according to the “seed” journal. While United States is responsible for about 84% and 81% of the most prolific authors to, respectively, ETP and JBV, its contribution to SBE is around 15%. In fact, the United Kingdom is the country that represents a larger proportion of prolific authors in SBE and the journal receives contributions from a wider group of countries such as The Netherlands, Sweden and Germany. 2.3. Data gathering considerations The purpose of the data collection phase was to compile and sort the citations obtained from the source journals selected: ETP, JBV and SBE. JBV and SBE are indexed to the Social Sciences Citation Index (SSCI), managed by the Institute for Scientific Information (ISI)’s 12 The years 1985-1986 for JBV and 1989-1991 for SBE were not included, since they were not available on ISI database. 27 Web of Science Service. 13 Thus, we started by exporting all the cited references included in SSCI of each of the articles published by JBV and SBE, from, respectively, 1987 and 1992 until February of 2009. 14 The procedure of data gathering for ETP journal was distinct, since SSCI did not provide any data prior to 2003. Thus, all the cited references of each article published between 1976 and February of 2009, were collected manually and typed in order to be processed. The citation database of each journal consisted of the relevant details of every cited reference: name of the author(s) of the cited reference, title of the cited reference, published source (i.e., title of the journal or book) and the year of publication. Citations extracted from SSCI, however, refer only the first author of the cited reference (authors who do not obtain first authorship are not represented), which bias the results and constitutes a database limitation for JBV and SBE. As previously mentioned, we did not consider as “articles” obituaries, corrections and editorial comments. Therefore, references/citations included in editorials, research notes, corrections, comments, replies and rejoinders were excluded. The data files of each journal were transferred to Microsoft Office Excel 2003 which enabled the harmonization and validation of the references/citations. Due to differences of format and text codification (for instance, in the names of the authors, 15 titles of the cited paper, titles of journals or books and edition’s year), between journals and within the journal itself, excel’s functions were used to standardize the citations’ sample. In relation to data distribution, a total of 2,598 articles were published in ETP (40%), JBV (27%) and SBE (33%), during the studied period 16 which originated a total of 91,172 citations. Thus, the average number of citations provided per article was 35. Analysing separately for each of the journals, JBV has the highest average of citations – 40 – followed by SBE with 34 and, finally, ETP with an average of 30 citations. 13 Social Sciences Citation Index (SSCI) is an interdisciplinary citation index, developed by the Institute for Scientific Information (ISI) and made available through the Web of Science service, that provides access to bibliographic and citation information from 2474 social sciences journals across more than 50 disciplines. Journals included in SSCI database are previously submitted to an objective evaluation process. 14 Cited references contained in articles from 1985 and 1986 for JBV and 1989, 1990 and 1991 for SBE were not included in the study due to its unavailability in ISI database. 15 Authors’ first name presented with two letters (e.g. Chrisman, J.J.) was restricted to one (e.g. Chrisman, J.). 16 From 1976 (ETP), 1987 (JBV) and 1992 (SBE) to February of 2009. 28 Table 7: Distribution of articles and citations per journals and year from 1992 to 2008 Entrepreneurship Theory and Practice Journal of Business Venturing Small Business Economics Number of Articles % Number of Citations % Average of citations per article Number of Articles % Number of Citations % Average of citations per article Number of Articles % Number of Citations % Average of citations per article 1992 18 4% 780 3% 43 34 6% 1001 4% 29 36 4% 816 3% 23 1993 25 5% 960 4% 38 36 6% 1276 5% 35 34 4% 779 3% 23 1994 27 6% 1154 4% 43 29 5% 1238 4% 43 48 6% 1201 4% 25 1995 15 3% 510 2% 34 27 5% 1118 4% 41 42 5% 1199 4% 29 1996 13 3% 558 2% 43 28 5% 1424 5% 51 40 5% 1106 4% 28 1997 14 3% 778 3% 56 30 5% 1381 5% 46 43 5% 1309 4% 30 1998 29 6% 1282 5% 44 28 5% 1286 5% 46 63 7% 2081 7% 33 1999 36 8% 1943 8% 54 28 5% 1276 5% 46 51 6% 1769 6% 35 2000 25 5% 1074 4% 43 23 4% 1208 4% 53 50 6% 1635 5% 33 2001 22 5% 1074 4% 49 27 5% 1611 6% 60 50 6% 1634 5% 33 2002 27 6% 1542 6% 57 29 5% 1659 6% 57 45 5% 1577 5% 35 2003 22 5% 1256 5% 57 43 8% 2071 7% 48 56 7% 2180 7% 39 2004 21 4% 1073 4% 51 45 8% 2339 8% 52 64 7% 2373 8% 37 2005 38 8% 2643 10% 70 35 6% 2150 8% 61 68 8% 2596 9% 38 2006 18 4% 1022 4% 57 40 7% 2365 8% 59 61 7% 2756 9% 45 2007 66 14% 4122 16% 62 41 7% 2205 8% 54 49 6% 2563 8% 52 2008 63 13% 3883 15% 62 35 6% 2248 8% 64 54 6% 2643 9% 49 Total 479 100% 25654 100% 54 558 100% 27856 100% 50 854 100% 30217 100% 35 29 Since the studied period differs according to the selected journal, Table 6 provides some insights regarding data distribution during the common period to all three journals: 1992 to 2008. ETP contributes with the minor proportion of articles and citations, obtaining an average of 54 citations per article. Analysing the evolution per year, ETP revels an increase on the average since 2005. SBE, on the contrary, is the major publisher of articles that provided the larger proportion of citations, having the lowest average of citations per article. After the consolidation of the citation databases, we were able to construct three distinct but complementary rankings, for each of the “seed” journals: the twentieth most cited authors; the tenth most cited studies and the twentieth most cited journals. The rankings allowed us to answer the first research question of the study, identifying the most cited authors, studies (article or book), and journals, in each of the entrepreneurship journals select. With the identification of the key authors we could then explore if there were similarities among the leading authors previously obtained and answer the second research question, through an analysis that implied gathering personal data on the authors’ educational background, research area and profession affiliation (cf., Figure 3). Figure 3: Methodological scheme 30 The mapping of the intellectual bases of the three “seed” journals combined with the analysis of the relationships between the most cited authors provides the fundamental tools to infer about the presence of invisible colleges in the entrepreneurship scientific field, answering the last research question and achieving the main purpose of the present study. 31 Chapter 3. Searching for the ‘invisible colleges’ in the Entrepreneurship literature: empirical results 3.1. Initial considerations The present chapter answers the three research questions posed in the study. The most cited authors, studies and journals are identified and the intellectual bases of each “seed” journal are explored on several levels (Section 3.2.). The linkages between the key scholars are analysed resorting to their educational background, research area and professional affiliation. The study is further developed with the inclusion of data concerning key scholars’ last affiliations (Section 3.3.). The evidence gathered from the applied analysis provides grounds to infer the presence of invisible colleges, answering the last research question and accomplished the main purpose of this study. 3.2. Who are the most cited authors, studies and journals in the last decades? The most cited author in ETP since its first publication until February, 2009, is Michael Wright (University of Nottingham, UK). The author ranks on the 71 st and 77 th positions in, respectively, JBV and SBE. The most cited author in JBV, from 1987 until February, 2009, 17 is Arnold Cooper (Purdue University, US), which takes the 3 rd and 37 th positions, respectively, in ETP and SBE’s ranking. Zoltan Acs is the most cited author in SBE, during the period of 1992 to February of 2009, 18 raking in 96 th in ETP and 126 th in SBE. Table 8 exhibit the 20 th most cited authors per journal, ordered by descending number of citations. The three Top 20 most cited authors’ rankings only have in common one author: Howard Aldrich (University of North Carolina, US). Similarities regarding top cited authors are notoriously higher between ETP and JBS than with SBE. ETP and JBV have nine top cited authors only common to them both, whereas JBV and SBE only share exclusively two authors and ETP and SBE have no top author common just to the two journals (cf. Table 8). 17 Cited references contained in articles from the initial publication’s years of 1985 and 1986 for JBV were not included in the study due to its unavailability in ISI database. 18 Cited references contained in articles from the initial publication’s years of 1989 to 1991 for SBE were not included in the study due to its unavailability in ISI database. 32 Table 8: Ranking of the Top 20 most cited authors in ETP, JBV and SBE (name and number of citations) Entrepreneurship Theory and Practice (ETP) Journal of Business Venturing (JBV) Small Business Economics (SBE) Name # Name # Name # Wright, M. 178 Cooper, A. 307 Acs, Z. 509 Zahra, S. 168 Aldrich, H. 241 Audretsch, D. 508 Cooper, A. 144 MacMillan, I. 213 Storey, D. 276 MacMillan, I. 138 Gartner, W. 209 Reynolds, P. 258 Brush, C. 122 Miller, D. 183 Evans, D. 248 Bygrave, W. 121 Porter, M. 183 Schumpeter, J. 173 Chrisman, J. 118 Zahra, S. 182 Porter, M. 130 Covin, J. 118 Shane, S. 180 Blanchflower, D. 126 Aldrich, H. 117 Vesper, K. 143 Geroski, P. 123 Hitt, M. 115 Hambrick, D. 141 Dunne, T. 116 Miller, D. 113 Covin, J. 135 Jovanovic, B. 116 Gartner, W. 112 Bygrave, W. 130 Cressy, R. 112 Westhead, P. 111 Birley, S. 129 Bates, T. 107 Sexton, D. 107 Eisenhardt, K. 128 Wagner, J. 100 Reynolds, P. 103 Schumpeter, J. 124 Baumol, W. 99 Sapienza, H. 103 Van de Ven, A. 121 Aldrich, H. 98 Hisrich, R. 100 Williamson, O. 120 Berger, A. 97 Birley, S. 90 Brockhaus, R. 118 Caves, R. 96 Dess, G. 87 Kanter, R. 116 Cohen, W. 94 Hambrick, D. 86 Timmons, J. 115 Davis, S. 93 Scherer, F. 93 Source: Authors computations based on our sample of citations in ETP, JBV and SBE collected manually for ETP and from Social Sciences Citation Index (SSCI) of the ISI Web of Science, for JBV and SBE. According to Zuccala’s (2006) methodology adopted in this study (see Section1.3.), there are three principal elements to take in consideration in the definition of invisible college: influential scholars (i.e. top cited authors); subject specialty (i.e. research areas) and information use environment (i.e. affiliation environment, such as institution and country). Following this method, we assigned a main research area to each of the most cited authors and analysed, for each “seed journal”, and for all journals combined, the geographical distribution of the authors’ current affiliation (Figure 4). 19 The designation of the core research areas is based on a comprehensive survey of the research themes on entrepreneurship, provided by Santos and Teixeira (forthcoming), which allowed us 19 Due to methodological convenience top cited authors’ affiliation (employer institution) and research area are exhibited in Table 12 (Section 3.3.). Common to all three journals Only common to ETP and JBV Only common to JBV and SBE Only common to ETP and SBE 33 to establish five distinct research areas within the entrepreneurship field. 20 Furthermore, the analysis of the academic publications and areas of interest of the most cited authors of each journal revealed that it was necessary to include two additional research areas (Labor and Industrial Organization), economic-oriented, outside the entrepreneurship field (Table 9). 21 Table 9: Areas of scientific research associated with top cited authors Research Areas Abbreviaton Entrepreneurship Theory Building ETB Characteristics of the Entrepreneur CE Corporate and Entrepreneurship Venturing CEV Entrepreneurship Education EE Innovation, Growth and Policy IGP Labor L Industrial Organization IO Analysing for all the “seed” journals, United States is the most prominent country, attracting around 79% of the most cited authors. United Kingdom comes in second, with 15%. Germany and Canada are less prominent, affiliating, respectively, two and one of the influential authors in entrepreneurship research. Regarding the research areas, CEV has the higher proportion of most cited authors (47%), followed by IGP (17%) and IO (13%). The other research areas have less influence. While this pattern is observed in the UK, in US, CEV remains the research area with more top cited scholars (46%), but it is followed by IO (14%). IGP represents 11%, along with CE and ETP. Overall, US is the only country with influential scholars in all the seven research areas. 20 Santos and Teixeira (forthcoming) identified eleven major topics on entrepreneurship literature: Entrepreneurship theory building; Entrepreneurial psychological issues; Demographic traits; Entrepreneurial context; Corporate entrepreneurship; Venture capital; Entrepreneurship education; Policy; Innovation; Growth and Regional. Due to the wide scope of academic interests reflected on the influential authors’ publications, we aggregated these topics into five, so that we could assign only one major research area to each of the authors – a requirement (and limitation) of the mapping constructions in this study (e.g. Figure 4 and 5). 21 Colours assigned to each scientific research are used in Section 3.3. 34 ETP JBV SBE ALL Figure 4: Mapping the international scientific linkages of the most influential authors in entrepreneurship by ‘seed journal’ Legend: ETB - Entrepreneurship Theory Building; CE – Characteristics of the Entrepreneur; CEV - Corporate and Entrepreneurship Venturing; EE - Entrepreneurship Education; IGP – Innovation, Growth and Policy; L – Labor; IO – Industrial Organization. 41 3.3. Are there any similarities/correlations between the most cited authors regarding their educational training and professional affiliation, and research area? In the previous section, we identified, trough a (co)citation analysis, 47 highly cited authors in the field of entrepreneurship. But co-citation techniques, though assessing the intellectual structure of a research field, do not capture all the insights related with the phenomenon of the invisible college (Zuccala, 2006). As Reader and Watkins (2006) point, are the highly cited authors strictly part of a set of ideas constructed in the minds of the citers; or is there an effective net of social interactions between the influential scholars? In order to answer this question, we complement the (co)citation analysis, exploring the possible collaborations between highly cited authors, based on the study of their affiliation, educational background and main research area. Table 12 exhibits personal data on the 47 most cited authors (employer institution, research area and granting school), 23 ranking them by the total number of citations obtained from the three selected journals. Among the most cited authors David Audretsch is the scholar with the highest number of citations received from all the “seed” journals, although he is not part of ETP and JBV’s rankings. Regarding key authors current affiliation – represented in the column “employer institution” – we observed that a total of 40 institutions employ the 47 most cited authors. 24 Harvard University (US) employs the highest number of most cited authors (5), followed by Babson College (US) and University of Minnesota (US), with three authors each and George Mason University (US) and New York University (US), both with two. The remaining 32 institutions employ only one influential author each. With respect to the organizations’ geographical distribution, US stands as the country where more institutions are located (29), followed by the UK (7) and then, Germany and Canada, with two institutions each. By combining the number of citations presented in Table 12, with the correspondent research area, for each cited author, we confirm the previous results regarding research areas. CVE is the main research area for twenty two influential authors, IGP attracts eight scholars, followed by IO, with six scholars. 23 Validity regarding data on the current Professional affiliation of the authors is only guaranteed until August of 2009. Due to the absence of information, it was no possible to identify the granting school of one author and the graduation year of four authors. 24 Note that three authors (Miller, Hambrick and Sexton) are affiliated with two institutions each. 42 Table 12: Information on the affiliation, educational background and research area of the 47 most cited authors Number of Citations Author ETP JBV SBE Employer institution Secondary unit Research Area Granting School (Ph.D.) Year 1 Audretsch, D. 48 39 508 Max Planck Institute of Economics, DE Entrepreneurship, Growth and Public Policy Group IGP University of Wisconsin-Madison, US 1980 2 Acs, Z. 32 37 509 George Mason University, US School of Public Policy IGP Graduate Faculty, The New School, US 1980 3 Cooper, A. 144 307 73 Purdue University (Retired), US Krannert School of Management (Retired) CEV Harvard University, US 1962 4 Aldrich, H. 117 241 98 University of North Carolina, US Kenan-Flagler Business School CEV University of Michigan, US 1969 5 Reynolds, P. 103 94 258 George Mason University, US School of Public Policy IGP Stanford University, US 1969 6 Gartner, W. 112 209 77 Clemson University, US Arthur M. Spiro Institute for Entrepreneurial Leadership ETB University of Washington, US 1982 7 Zahra, S. 168 182 38 University of Minnesota, US Carlson School of Management CEV University of Mississippi, US 1982 8 Porter, M. 55 183 130 Harvard University, US Harvard Business School CEV Harvard University, US 1973 9 MacMillan, I. 138 213 14 University of Pennsylvania, US Wharton School of Business CEV University of South Africa, ZA 1975 10 Storey, D. 49 36 276 University of Warwick, UK Warwick Business School IGP Newcastle University, UK 1978 11 Schumpeter, J. † 49 124 173 Harvard University, US - EBT University of Vienna, AT 1906 12 Miller, D. 113 183 42 University of Montréal and University of Alberta, CA Ecole des Hautes Etudes Commerciales and Family Enterprise and Strategy CEV McGill University, CA 1976 13 Shane, S. 78 180 78 Case Western Reserve University, US Weatherhead School of Management EBT University of Pennsylvania, US 1992 14 Evans, D. 13 48 248 Law and Economics Consulting Group (LECG) Europe, UK - IGP University of Chicago, US 1983 15 Bygrave, W. 121 130 33 Babson College, US - CEV - - 16 Birley, S. 90 129 54 Bae Sistems (Retired), UK - CEV N/a N/a 17 Covin, J. 118 135 17 Indiana University, US Kelley School of Business CEV University of Pittsburgh, US 1985 18 Wright, M. 178 47 35 University of Nottingham, UK Nottingham University Business School CEV University of Nottingham, UK N/a 19 Brush, C. 122 86 36 Babson College, US - CE - - 20 Westhead, P. 111 47 85 University of Durham, UK Durham Business School CEV University College of Wales, UK 1988 21 Hambrick, D. 86 141 12 Pennsylvania State University and Columbia University, US Smeal College of Business and Graduate School of Business CEV Pennsylvania State University, US 1979 22 Williamson, O. 35 120 79 University of California, Berkeley, US Walter A. Haas School of Business CEV Carnegie Mellon University, US 1963 23 Vesper, K. 64 143 15 University of Washington, US University of Washington Business School EE Stanford University, US 1969 24 Eisenhardt, K. 63 128 26 Stanford University, US Department of Industrial Engineering and Engineering Management CEV Stanford University, US 1982 25 Hisrich, R. 100 87 28 Thunderbird School of Global Management, US Walker Center for Global Entrepreneurship CEV University of Cincinnati, US 1971 43 (…) Number of Citations Author ETP JBV SBE Employer institution Secondary unit Research Area Granting School (Ph.D.) Year 26 Sexton, D. 107 96 11 Ohio State University (Retired)/ Ewing Marion Kauffman Foundation, US - CEV Ohio State University, US 1972 27 Van de Ven, A. 81 121 11 University of Minnesota, US Carlson School of Management IGP University of Wisconsin, US 1972 28 Timmons, J. † 75 115 20 Babson College, US - CEV Harvard University, US 1971 29 Sapienza, H. 103 80 27 University of Minnesota, US Carlson School of Management CEV University of Maryland, US 1989 30 Bates, T. 25 76 107 Wayne State University, US Department of Economics CE University of Wisconsin, US 1972 31 Brockhaus, R. 63 118 13 Saint Louis University, US John Cook School of Business CE University of Washington , US 1976 32 Hitt, M. 115 59 9 Texas A&M University, US Mays Business School CEV University of Colorado, US 1974 33 Chrisman, J. 118 47 15 Mississippi State University, US College of Business and Industry CE University of Georgia, US 1986 34 Dess, G. 87 78 14 University of Texas at Dallas, US School of Management CEV University of Washington, US 1980 35 Baumol, W. 20 48 99 New York University, US Leonard N. Stern School of Business ETB University of London, UK 1949 36 Kanter, R. 47 116 3 Harvard University, US Harvard Business School CEV University of Michigan, US 1967 37 Cohen, W. 11 53 94 Duke University, US Fuqua School of Business IGP Yale University, US 1981 38 Blanchflower, D. 5 9 126 Dartmouth College, US Department of Economics L University of London, UK 1985 39 Caves, R. 10 34 96 Harvard University, US Department of Economics IO Harvard University, US 1958 40 Geroski, P. † 3 9 123 University of London, UK London Business School IGP University of Warwick, UK N/a 41 Jovanovic, B. 4 14 116 New York University, US Department of Economics IO University of Chicago, US 1978 42 Cressy, R. 4 12 112 University of Birmingham, UK Birmingham Business School CEV University of Edinburgh, UK N/a 43 Scherer, F. 11 24 93 Harvard University, US John F. Kennedy School of Government IO University of Michigan, US 1954 44 Dunne, T. 0 10 116 Federal Reserve Bank of Cleveland, US Research Department IO Pennsylvania State University, US 1987 45 Berger, A. 9 11 97 University of South Carolina, US Moore School of Business IO University of California, Berkeley, US 1983 46 Wagner, J. 12 4 100 University of Lueneburg, DE Institute of Economics IO University of Hannover, DE 1984 47 Davis, S. 6 6 93 University of Chicago, US Booth School of Business L Brown University, US 1986 Note: Authors are ordered by the total of citation in each journal. The grey cells indicate that the author is part of the Top 20 most cited authors in the designated journal Legend: ETB - Entrepreneurship Theory Building; CE – Characteristics of the Entrepreneur; CEV - Corporate and Entrepreneurship Venturing; EE - Entrepreneurship Education; IGP – Innovation, Growth and Policy; L – Labor; IO – Industrial Organization. 44 CE, ETB, L and EE are less prominent areas of interest. CVE is the most frequent research area associated with ETP and JBV, while in SBE, IGP domains, as previously investigated. Beyond that, we can also draw further evidence: IGP, in spite of not being the most frequent research area, is the main research area for the two most cited authors – Audretsch and Acs – among the 47. Another point should be stressed: the bottom of top cited authors are exclusively associated with SBE (they are seldom cited by ETP and JBV) and eight of them are related with economic-oriented areas, whereas ETP and JBV do not rank in the top 20 any authors with research areas non-related with entrepreneurship. These findings support the preceding evidence that suggests that the three entrepreneurship “seed” journals embody two (in)visible colleges in the entrepreneurship field: one associated with ETP and JBV and the other associated with SBE. Educational training is also explored gathering information concerning the institution that granted the PhD degree to the cited authors (if that is the case) and respectively, the graduation year. We identify 31 distinct universities that granted the doctoral degree to 44 of the most cited authors. Harvard University (US) granted 4 PhDs, followed by the Stanford University US), University of Michigan (US) and University of Washington (US), which granted 3 PhDs each. Pennsylvania State University (US), University of Chicago (US), University of Wisconsin (US) and University of London (UK) have two PhDs each among the most cited authors. The remaining 23 universities granted a PhD to only one top cited author. The geographical distribution of the cited authors’ granting schools has a similar pattern to the one concerning their affiliation. US concentrates the vast majority of the universities (33), followed by UK (7). The only two differences are the inclusion of New Zealand and Austria, in the granting schools of the most cited authors. Observing the graduation year, we infer that the 44 PhD most cited authors hold their degree for a relatively long time (the PhD degree most recent was granted 17 years ago and belongs to Scott Shane). According to Zuccala (2006) the Information Use Environment is a key element to identify the invisible colleges, representing a scientific workspace where information related behaviours occur. Based on this concept, we include additional information regarding the academic experience of the most cited authors, so that our analysis captures all the (invisible) links between the key scholars. Thus, to infer if there are social correlations between the highly 45 cited authors, in addition to PhD’s university and current professional affiliation, we gather data concerning other current affiliations, besides the main employer institution, and present visiting academic institutions along with data on previous affiliations 25 and past visiting academic institutions (Table A5 provides, in detail, the information collected with respect to these two items). 26 Figure 5 illustrates graphically the links between the highly cited authors, based on the academic institutions that received the authors over their professional career. We only considered institutions that had received or are currently employing more than two top cited authors, which give us a total of 24 institutions. 27 The map represents the links between a total of 44 top cited authors, through 24 organizations. Each of the top cited authors is identified by their rank number established in Table 11, as well as, the respective research area colour. Each link is represented by a straight lines and denotes that at least one top cited author worked in the two linked institutions. An overall analysis of the map tells us that all institutions have received at least one top cited author which suggests a substantial degree of correlation between the most cited authors in entrepreneurship research. The connections between the institutions and number of influential authors associated with them are distinct, according to each institution. Harvard University (US) is the institution that gathers the highest number of top cited authors (9), followed by the University of Pennsylvania (US), with 7 key authors. A total of 12 institutions is attach with 3 top cited authors. The University of Pennsylvania (US) holds the highest number of links (11), which implies that top cited authors connect with others, trough 11 distinct institutions. University of London (UK) comes in second, being connected with 10 institutions. The least interactive institutions, among the top ones, are the University of Michigan (US) and the University of Washington (US), with, respectively, 2 and 3 links. 25 The past affiliations previous to cited authors’ doctoral degree were disregarded. 26 Due to the absence of information we did not gathered information on current and past affiliations/visiting academic institutions for six cited authors. 27 A previous attempt was made in order to include institutions with more than one highly cited author but the number of institutions obtained (48) plus the inherent linkages among them did not permit a graphical representation. 46 Figure 5: Mapping links among top cited authors in entrepreneurship scientific area Note: Each link means that at least two top cited authors worked in the two linked organizations ETB Entrepreneurship Theory Building CE Characteristics of the Entrepreneur CEV Corporate and Entrepreneurship Venturing EE Entrepreneurship Education IGP Innovation, Growth and Policy IO Industrial Organization L Labor U. London (UK) Babson C. (US) U. Chicago (US) U. Michigan (US) U. Minnesota (US ) U. Durham (UK) U. South Carolina (US) New York U. (US) U. Washington (US) U. Pennsylvania (US) Stanford U. (US) SSCB (DE) U. Nottingham (UK) U. California B. (US ) Indiana U. (US) MPIE (DE) U. Maryland (US) EMKF (US) Harvard U. (US) INSEAD (FR) Baylor U. (US) Columbia U. (US) U. Warwick (UK) ICL (UK) 39 3 7 3 36 8 43 11 28 22 45 41 5 27 13 3 9 38 5 40 14 15 35 19 15 7 28 23 5 5 23 24 3 4 10 40 20 22 42 5 27 7 29 41 14 9 35 2 21 9 12 23 34 31 6 47 2 29 13 23 26 31 5 15 18 1 2 14 45 33 29 1 17 22 43 4 36 41 47 14 1 2 46 15 18 20 45 22 30 1 2 26 16 13 20 1 10 20 47 One should notice that the number of top cited authors associated with an institution is not, per se, an indicative of the degree of connectivity between influential authors. For instance, the University of Michigan (US) receives 4 top cited authors but only links with 2 other institutions. On the other hand, the Social Science Centre of Berlin (DE) receives only 3 top cited authors, but establishes connections with 9 distinct institutions, which attests for the top cited authors’ professional mobility, confirmed when we identify two of the cited authors, Audretsch and Acs, the two most cited authors in our study and renowned academics, with a vast and productive career. An analysis on the research area of the 44 top cited authors indicates that the degree of collaboration, represented by the links between institutions, agrees with the initial distribution of authors through the research areas, i.e., the majority of the links established belong to top cited authors, whose main research area is CVE, IGP appears in second, followed by IO. The exception to this pattern comes from the research area of EE that, with only one top cited author, connects with 4 other institutions, overcoming the research area of Labor (L) that has two influential authors with no established collaborations outside their current affiliation. The evidence obtained indicates that top cited authors are highly connected, which is particularly visible to the research areas of CVE and IGP. 3.4. Are there different “invisible colleges” in entrepreneurship research area? Identifying the most cited authors, studies and journals for the three “seed” journals allowed us to explore the intellectual structure of entrepreneurship research. Evidence supports the multidisciplinary nature of the entrepreneurship field, when results show that highly influential authors in the field of entrepreneurship are working in several subject specialities, including research areas not so entrepreneurship focussed, like economics. These so called “nonentrepreneurship” researchers are highly related with the specific orientation of each of the “seed” journals. The present study empirically corroborates the idea that ETP and JBV are the most influential journals in the entrepreneurship field and SBE is, indeed, economic oriented, embodying economic-oriented researchers among the most cited authors. In fact, the (co) citation analysis confirms several similarities between ETP and JBV regarding the most cited authors, studies and journals and main research area and attests for the distinct intellectual structure of SBE. 48 To infer the presence of invisible colleges it is crucial to include in the analysis the informal channels of scientific communication. Thus, the second stage of the study consisted in exploring the informal communication links between highly cited authors. By collecting personal data regarding top cited authors’ current and past affiliation, educational background and combining it with the research areas assigned, one could infer about the social ties established among the top cited authors. The results reveal that 44 key authors are highly correlated among themselves, through 24 distinct institutions where they developed or are currently developing their work. The evidence provided by the two stages of the study fulfils the key elements to assess the existence of invisible colleges: social actors (the most cited authors); subject specialty (research areas) and information use environment (professional affiliation of the most cited authors). Formal and informal communication is represented by, respectively, the most cited studies/journals and affiliations’ linkages. Thus, it is possible to identify two invisible colleges: one associated with ETP and JBV journals and the other associated with SBE. The results obtained are summarized in Figure 6. Social actors are represented by the top five most cited authors of each “seed” journal ; the scientific research area that attracts the highest number of most cited authors is the “subject specialty” and the information use environment is defined by the professional affiliation where more highly cited authors currently (until August 2009) work. Formal and informal communication is given, respectively, by the top five studies and journals for each of the three journals and the linkages extracted from information regarding top cited authors’ current and past affiliations and PhD granting affiliation. When examining the evidence exhibited in Figure 6, we confirm previous assessment concerning the intellectual proximity of ETP and JBV journals and their distance towards SBE’s intellectual bases. The formal channels of communication further enhance, on one hand, the similarities between ETP and JBV and, on the other, the differences regarding SBE: the top five cited studies and top five cited journals are quite similar between ETP and JBV, while the evidence for SBE empirically shows that this journal values economic-related topics. Informal ties also corroborate the findings: ETP and JBV have more affiliations in common than with SBE and the geographical distribution of the affiliations’ pattern also differ from ETP/JB (where the US supremacy prevails) to SBE (where UK and Germany have a significant impact). 49 Figure 6: Invisible colleges in entrepreneurship research Notes: Universities listed in “Informal Communication” have affiliated at least 3 of the most cited authors in the Journal (++) or have affiliated 2 of the most cited authors in the Journal who have more than 3 links with universities that also affiliates most cited authors in the Journal(+) 50 One should point that the evidence regarding links among the most cited authors reveals a strong interaction among scholars from the two invisible colleges, which means that they are not isolated from each other or even from influential authors of other scientific fields. 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Journal of Small Business Management. Level II 1. Entrepreneurship, Innovation and Change. 2. Family Business Review. 3. International Journal of Entrepreneurship Development, Education and Training. 4. International Journal of Entrepreneurship. 5. International Journal of Technological Innovation and Entrepreneurship. 6. Journal of Developmental Entrepreneurship. 7. Journal of Enterprising Culture. 8. Journal of Entrepreneurship Education. 9. Journal of Private Enterprise. 10. New England Journal of Entrepreneurship. 11. Small Business and Enterprise Development. Level III 1. Economic Analysis: A Journal of Enterprise and Participation. 2. Enterprise and Innovation Management Studies. 3. Entrepreneurship Development Review. 4. Journal of Entrepreneurship. 5. Journal of International Business and Entrepreneurship. 6. Journal of Technology Transfer. 7. Small Enterprise Research: The Journal of SEAANZ. 8. Studies in Cultures, Organizations and Societies. Source: Adapted from http://www.marketingtechie.com/articles/mtart20020307.pdf 62 Table A 2: Ranking of the Top 10 most cited articles in Entrepreneurship Theory and Practice Entrepreneurship Theory and Practice Author(s) Year Article Title Journal Number of times cited Gartner, W. 1988 "Who is an entrepreneur?" is the wrong question American Journal of Small Business 63 Shane, S.;Venkataraman, S. 2000 The promise of entrepreneurship as a field of research Academy of Management Review 59 Barney, J. 1991 Firm resources and sustained competitive advantage Journal of Management 57 Gartner, W. 1985 A conceptual framework for describing the phenomenon of new venture creation Academy of Management Review 57 Low, M.;MacMillan, I. 1988 Entrepreneurship: Past research and future challenges Journal of Management 49 Covin, J.;Slevin, D. 1991 A conceptual model of entrepreneurship as firm behavior Entrepreneurship Theory and Practice 45 Lumpkin, G.;Dess, G. 1996 Clarifying the entrepreneurial orientation construct and linking it to performance Academy of Management Review 44 Jensen, M.;Meckling, W. 1976 Theory of the firm: Managerial behavior, agency costs and Ownership structure Journal of Financial Economics 43 Busenitz, L.;Barney, J. 1997 Differences between entrepreneurs and managers in large organizations: Biases and heuristics in strategic decision making Journal of Business Venturing 40 Katz, J.;Gartner, W. 1988 Properties of emerging organizations Academy of Management Review 39 Miller, D. 1983 The correlates of entrepreneurship in three types of firms Management Science 39 Source: Authors computations based on our sample of citations in ETP, JBV and SBE collected manually for ETP and from Social Sciences Citation Index (SSCI) of the ISI Web of Science, for JBV and SBE. Common to all three journals Only common to ETP and JBV Only common to JBV and SBE Only common to ETP and SBE 63 Table A 3: Ranking of the Top 10 most cited articles in Journal of Business Venturing Journal of Business Venturing Author(s) Year Article Title Journal Number of times cited Low, M.;MacMillan, I. 1988 Entrepreneurship: Past research and future challenges Journal of Management 59 Gartner, W. 1985 A conceptual framework for describing the phenomenon of new venture creation Academy of Management Review 56 Jensen, M.;Meckling, W. 1976 Theory of the firm: Managerial behavior, agency costs and Ownership structure Journal of Financial Economics 53 MacMillan, I.;Siegel, R.;Subbanarasimha, P. 1985 Criteria used by venture capitalists to evaluate new venture proposals Journal of Business Venturing 47 Shane, S.;Venkataraman, S. 2000 The promise of entrepreneurship as a field of research Academy of Management Review 46 Sandberg, W.;Hofer, C. 1987 Improving new venture performance: The role of strategy, industry structure, and the entrepreneur Journal of Business Venturing 44 Barney, J. 1991 Firm resources and sustained competitive advantage Journal of Management 39 Cohen, W.;Levinthal, D. 1990 Absorptive capacity: A new perspective on learning and innovation Administrative Science Quarterly 35 Covin, J.;Slevin, D. 1989 Strategic management of small firms in hostile and benign environments Strategic Management Journal 35 Venkataraman, S. 1997 The distinctive domain of entrepreneurship research Advances in Entrepreneurship, Firm Emergence and Growth 35 Source: Authors computations based on our sample of citations in ETP, JBV and SBE collected manually for ETP and from Social Sciences Citation Index (SSCI) of the ISI Web of Science, for JBV and SBE. Common to all three journals Only common to ETP and JBV Only common to JBV and SBE Only common to ETP and SBE 64 Table A 4: Ranking of the Top 10 most cited articles in Small Business Economics Small Business Economics Author(s) Year Article Title Journal Number of times cited Jovanovic, B. 1982 Selection and the evolution of industry Econometrica 91 Evans, D.;Jovanovic, B. 1989 An estimated model of entrepreneurial choice under liquidity constraints Journal of Political Economy 75 Stiglitz, J.;Weiss, A. 1981 Credit rationing in markets with imperfect information American Economic Review 52 Acs, Z.;Audretsch, D. 1988 Innovation in large and small firms: An empirical analysis American Economic Review 49 Dunne,T.; Roberts, M.;Samuelson, L. 1989 The growth and failure of U.S. manufacturing plants Quarterly Journal of Economics 49 Evans, D.;Leighton, L. 1989 Some empirical aspects of entrepreneurship American Economic Review 47 Evans, D. 1987 Tests of alternative theories of firm growth Journal of Political Economy 45 Audretsch, D.;Feldman, M. 1996 R&D spillovers and the geography of innovation and production American Economic Review 44 Evans, D. 1987 The relationship between firm growth, size and age: Estimates for 100 manufacturing industries. Journal of Industrial Economics 43 Lucas, R. 1978 On the size distribution of business firms Bell Journal of Economics 40 Source: Authors computations based on our sample of citations in ETP, JBV and SBE collected manually for ETP and from Social Sciences Citation Index of the ISI Web of Science, for JBV and SBE. Common to all three journals Only common to ETP and JBV Only common to JBV and SBE Only common to ETP and SBE 65 Table A 5: Information on current and previous affiliations/ visiting academic institutions Author Affiliations/ Visiting Academic Institutions a Previous Affiliations/ Visiting Academic Institutions b Indiana University, US Georgia State University, US Ewing Marion Kauffman Foundation, US Middlebury College, US Friedrich-Schiller-University Jena, DE Social Science Centre Berlin, DE ZEW, Centre for Economic Research, DE University of Durham, UK CEPR, Centre for Economic Policy Research, UK Kiel Institute of World Economics, DE EIM Consulting for Small and Medium-Sized Business, NL Tinbergen Institute, NL Max Planck Institute of Economics, DE University of Maryland, US University of Baltimore, US Social Science Centre Berlin, DE Ewing Marion Kauffman Foundation, US University of Illinois Springfield, US - Manhattan College, US - Columbia University, US - Middlebury College, US - Santa Anna School of Advanced International Studies, IT - Université Aix-Marseille II, FR - University of St Andrews, UK Harvard University, US Stanford University, US - University of Pennsylvania, US - University of Manchester, UK - International Institute for Management Development, CH - Cornell University, US - Stanford University, US - International Institute of Management, DE - University of Oxford, UK - Centre for Environmental Studies, UK - Universita' Commerciale Luigi Bocconi, IT - Wirtschaftsuniversität Wien, AT - BI Norwegian School of Management, NO - Universita' degli Studi di Trento, IT - University of British Columbia, CA - Keio University, JP - Jönköping University, SE - Universitat Autònoma de Barcelona, ES - Florida International University, US - University of London, UK - Babson College, US - Marquette University, US - University of Minnesota, US - University of Pennsylvania, US - INSEAD, European Institute of Business Administration, FR - University of Southern California, US - San Francisco State University, US - Georgetown University, US - Babson College, US - Georgia State University, US 8 Porter, M. - - - New York University, US - Columbia University, US University of Reading, UK - University of Manchester, UK - University of Durham, UK - 11 Schumpeter, J. † - - - McGill University, CA - Columbia University, US Audretsch, D.1 Acs, Z.2 Cooper, A.3 Aldrich, H.4 Reynolds, P.5 Gartner, W.6 Zahra, S.7 MacMillan, I.9 Storey, D.10 Miller, D.12 66 (…) Author Affiliations/ Visiting Academic Institutions a Previous Affiliations/ Visiting Academic Institutions b - Imperial College London, UK - University of Maryland, US - National University of Singapore, SG - Massachusetts Institute of Technology, US - Georgia Institute of Technology, US University of London, UK Fordham University, US - Social Science Centre Berlin, DE - New York University, US University of London, UK University of Nottingham, UK - INSEAD, European Institute of Business Administration, FR - Bryant University, US - Boston University, US - University of Massachusetts Dartmouth, US 16 Birley, S. - Imperial College London, UK 17 Covin, J. - Georgia Institute of Technology, US Erasmus University Rotterdam, NL EMLYON Business School, FR INSEAD, European Institute of Business Administration, FR University of Ghent, BE University of Siena, IT - Norwegian University of Science and Technology, NO Boston University, US - Jönköping University, SE Bodø University College, NO - University of Warwick, UK - University of Stirling, UK - University of Nottingham, UK - Imperial College London, UK 21 Hambrick, D. - - - Australian National University, AU - Panthéon-Sorbonne University, FR - Northwestern University, US - Saarland University, DE - Indiana University, US - Harvard University, US - University of Kyoto, JP - University of Warwick, UK - Baylor University, US - Babson College, US - University of Calgary, CA 24 Eisenhardt, K. - - 25 Hisrich, R. - Case Western Reserve University, US 26 Sexton, D. - Baylor University, US - University of Pennsylvania, US - Kent State University, US - Northeastern University, US - Boston College, US - Colgate University, US 29 Sapienza, H. - University of South Carolina, US 13 Shane, S. 23 Vesper, K. 27 Van de Ven, A. 20 Westhead, P. 22 Williamson, O. 18 Wright, M. 19 Brush, C. 14 Evans, D. 15 Bygrave, W. 28 Timmons, J. †