The Fulfillment Center Intervention Study: Protocol for a group-randomized control trial of a participatory workplace intervention

Kelly, Erin L.; Siebach, Kirsten F.; DeHorn, Grace; Lovejoy, Megan Article — Published Version The Fulfillment Center Intervention Study: Protocol for a group-randomized control trial of a participatory workplace intervention PLOS ONE Provided in Cooperation with: WZB Berlin Social Science Center Suggested Citation: Kelly, Erin L.; Siebach, Kirsten F.; DeHorn, Grace; Lovejoy, Megan (2024) : The Fulfillment Center Intervention Study: Protocol for a group-randomized control trial of a participatory workplace intervention, PLOS ONE, ISSN 1932-6203, Public Library of Science (PLoS), San Francisco, CA, Vol. 19, Iss. 7, pp. 1-18, https://doi.org/10.1371/journal.pone.0305334 This Version is available at: https://hdl.handle.net/10419/312553 Standard-Nutzungsbedingungen: Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden. 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If the documents have been made available under an Open Content Licence (especially Creative Commons Licences), you may exercise further usage rights as specified in the indicated licence. http://creativecommons.org/licenses/by/4.0/ STUDY PROTOCOL The Fulfillment Center Intervention Study: Protocol for a group-randomized control trial of a participatory workplace intervention Erin L. Kelly 1 *, Kirsten F. SiebachID 2 , Grace DeHorn 3 , Megan Lovejoy 4 1MIT Institute for Work and Employment Research and MIT Sloan School of Management, Massachusetts Institute of Technology, Cambridge, MA, United States of America, 2Bloomberg School of Public Health, John Hopkins University, Baltimore, MD, United States of America, 3MIT Institute for Work and Employment Research, Massachusetts Institute of Technology, Cambridge, MA, United States of America, 4T.H. Chan School of Public Health and Harvard Center for Population and Development Studies, Harvard University, Cambridge, MA, United States of America *[email protected] Abstract Warehousing and storage is an economically vital industry, with 1.2 million workers in 2020. The Fulfillment Center Intervention Study focuses on workers in fulfillment centers in the ecommerce segment of this industry. Fulfillment centers are a growing yet understudied work environment which provides a unique setting to further examine how working conditions and worker voice influence health. The Study involves a group-randomized controlled trial comparing participants in worksites randomized to launch the participatory intervention (Health and Well-Being Committees, or HaWCs) with participants working for the same firm in control sites. HaWCs serve as a new formal voice channel where a small group of frontline workers and supervisors solicit workers’ concerns and ideas about safety (e.g., physical hazards), the psychosocial environment (e.g., how workers feel about their treatment at work), and work organization (e.g., workflow, training opportunities, scheduling) and then develop and implement improvement projects in response. The primary objectives of the study are to evaluate the efficacy of the HaWC intervention and its effect on mental health outcomes and changes in the conditions of work within fulfillment centers, and to conduct a process evaluation of key contextual factors that support effective intervention implementation and sustained engagement. To our knowledge, this will be the first trial of a participatory intervention within a fulfillment center setting. Anticipated challenges include competing demands and company initiatives that may limit management support and high turnover. Should the intervention be shown to be feasible, the outcomes from this study will inform future randomized controlled trials of participatory interventions. Trial registration: This trial is registered with the ClinicalTrials.gov registry (NCT05199415) and approved by the Institutional Review Board (IRB) at the Massachusetts Institute of Technology (Protocol: 200800024). PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0305334 July 18, 2024 1 / 18 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Kelly EL, Siebach KF, DeHorn G, Lovejoy M (2024) The Fulfillment Center Intervention Study: Protocol for a group-randomized control trial of a participatory workplace intervention. PLoS ONE 19(7): e0305334. https://doi.org/10.1371/ journal.pone.0305334 Editor: Nhat Tan Pham, International University - Vietnam National University Ho Chi Minh City, VIET NAM Received: December 13, 2023 Accepted: May 26, 2024 Published: July 18, 2024 Copyright: ©2024 Kelly et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: No datasets were generated or analysed during the current study. All relevant data from this study will be made available upon study completion. Funding: This study was supported by the National Institute for Occupational Safety and Health grant 1155034-5119517 to ELK. https://grants.nih.gov/ grants/guide/pa-files/PAR-20-297.html. Additional funding was provided to ELK by the MIT IWER Good Companies, Good Jobs Initiative (https:// Introduction The work environment is an important social determinant of mental and physical health. Poor working conditions, including high job strain [1,2], non-standard work schedules, long hours [3,4], limited schedule control [5,6], and limited voice [7] (i.e., workers’ opportunities to share ideas and concerns about their work environment) are associated with higher risk of injury and low job satisfaction [8] as well as common mental disorders, such as anxiety and depression, and poor psychological well-being [9]. Poor mental health can have a negative impact on health across the life course, including increased disability and higher risk of chronic diseases and premature mortality risk [10,11], whereas positive psychological wellbeing predicts healthier aging and greater longevity [12]. Healthy and supportive work environments are not only important for the individual health of workers, but also for the economy more broadly. A 2022 report estimated that poor mental health in the U.S. workforce costs the economy $47.6 billion each year in lost productivity [13]. The Warehousing and Storage industry provides a unique setting to further examine how working conditions and specifically worker voice influence health. This industry has experienced rapid growth in recent years; employment has nearly doubled since 2000 to 1.2 million workers in 2020 [14]. Much of this growth has been fueled by the rise of e-commerce (i.e., buying and selling goods on the Internet), a segment of the warehousing industry that relies on work done in fulfillment centers; data on the fulfillment center workforce specifically is more limited. Fulfillment center sales rose by 52%, contributing to a 37% increase in employment in the broader warehousing industry, between 2014 and 2017 [15]. Black and Latino workers are overrepresented in fulfillment centers, as compared to the overall U.S. labor force (Black workers: 25% vs. 12.3%; Latino workers: 35% vs. 18%) [15]. The racial and ethnic diversity of this workforce both reflects the future of American demographics and exposes workers already facing systemic health inequities to difficult working conditions. Given this growth and composition, it is critical to investigate factors that influence worker health in fulfillment centers. In the midst of this growth, and especially in light of the increased demand absorbed by these workers during the COVID-19 pandemic, it is important to understand how the conditions of work in fulfillment centers affect workers’ health. Fulfillment center workers face conditions that have been demonstrated to affect health in other industries, including high job strain (high job demands and low job control [1]), non-standard schedules, long hours [3], and limited schedule control [5] that affects sleep duration [16] and increases work-family conflict [6,17,18]. These work conditions also increase the risk for common mental disorders, poor psychological well-being, and injury [9]. Data on fulfillment centers are limited, but the warehousing, transportation, and utilities sector has among the highest prevalence of low job control, anxiety, stress, and neurotic disorders [19]. Risks of injury and illness are high, with an incidence rate of 5.1 for warehousing and storage compared to 3.1 for all industries and twice the rate for cases with days away from work [20]. Fulfillment center workers have few opportunities for exercising “voice,” a key component of our proposed intervention. Perceived voice—the ability to express opinions to improve work conditions [21] predicts job satisfaction and contentment [7]. Unions have historically provided a voice mechanism through which workers could share their concerns and influence how work is accomplished, however union representation within fulfillment centers is sparse [7,12]. Filling the gap in research as it pertains to the health impacts of working conditions within fulfillment centers, including voice as another measure of the psychosocial work environment, can provide critical guidance for the development of strategies that will improve population more health broadly. PLOS ONE The Fulfillment Center Intervention Study PLOS ONE | https://doi.org/10.1371/journal.pone.0305334 July 18, 2024 2 / 18 mitsloan.mit.edu/institute-work-and-employmentresearch/about-iwer) and the MIT Sloan Health Systems Initiative (https://mitsloan.mit.edu/ centers-initiatives/health-systems-initiative/healthsystems-initiative-welcome). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: NO authors have competing interests. The Total Worker Health (TWH) approach, developed by the National Institute of Occupational Safety and Health (NIOSH) aims to improve the work environment and promote workrelated health and well-being through the integrated redesign of workplace policies, programs, and practices. TWH approach uses an integrated approach to improving well-being by combining a traditional concern with safety and protection from injury with a focus on conditions such as workplace psychosocial supports and the organization of work which are related to health promotion and other components of health and well-being more broadly [22]. Interventions employing this approach have demonstrated effectiveness in improving risk factors for injuries and illness across a range of industries, including manufacturing, services, health care, construction, telecommunications, and transportation [23,24]. In their review of TWH intervention studies, Anger and colleagues [23] found that all but one of the included studies demonstrated statistically significant improvements on study outcomes. The authors concluded that TWH-oriented interventions that address both injuries and broader wellness and well-being outcomes can improve workforce health effectively and more rapidly than traditional programs focused exclusively on occupational safety and health. Our study responds to a growing interest in participatory interventions, which create structured opportunities to exercise voice and involve workers in problem solving [25–28]. According to Nielsen and Randall [29], a participatory workplace intervention includes involving workers in intervention design, identifying areas of improvement, developing action plans, implementing action plans, and evaluating the results of the intervention [29]. From the perspective of voice research, participatory interventions give workers the opportunity to influence how they do their work (i.e., often aim to increase job control) but also provide opportunities to share ideas, concerns, and expertise more broadly. Unlike more traditional voice mechanisms such as unions, participatory interventions are unique in that they involve input from both management and workers seeking mutually beneficial solutions. Participatory interventions can therefore be understood as a new voice mechanism, a new channel for workers’ input into the organizational environment. On-going interventions, in particular, provide repeated opportunities to share concerns and ideas; those who are most directly involved also have the opportunity to contribute to planning and implementing changes in their workplace. Participatory workplace interventions have demonstrated positive effects on worker wellbeing [30]. Previous research has shown that worker participation is an essential aspect of effective organizational interventions [31] and that worker participation can improve health and safety [32,33]. Cross-sectional research finds that worker involvement is associated with higher job satisfaction, less fatigue, and lower odds of injury [34]. The adoption of safety committees [35] with a broader scope and higher worker involvement is associated with fewer injuries [36]. Despite these clear potential benefits for worker well-being, the integrated and participatory TWH approach has yet to be studied in the fulfillment center work environment. The aim of this paper is to present the study protocol of a cluster randomized trial designed to evaluate the effectiveness of a participatory intervention of Health and Well-being Committees (HaWCs) in fulfillment centers consistent with the TWH model. The primary study hypotheses were that workers in fulfillment centers randomized to receive this 12-month intervention would have reduced psychological distress and improved psychological wellbeing compared to those individuals in control sites. The process evaluation will document how the intervention is implemented across each intervention site. Methods The description of the study follows the CONSORT statement, with the extension for a cluster randomized trial [37]. PLOS ONE The Fulfillment Center Intervention Study PLOS ONE | https://doi.org/10.1371/journal.pone.0305334 July 18, 2024 3 / 18 Study design The study is a two-arm cluster randomized-controlled trial. The units of analysis are individuals within the cluster of fulfillment centers. There are three measurement time points: baseline measured prior to randomization (T1), 6 months after baseline (T2), and 12 months after baseline (T3). Process evaluation data will be collected for approximately 30 months, from baseline through 18 months after the T3 survey. The study has been registered with the ClinicalTrials. gov registry (NCT05199415) and approved by the Institutional Review Board (IRB) at the Massachusetts Institute of Technology (Protocol: 200800024). Any changes to the protocol will be approved by the IRB. Study setting, population, and recruitment The study utilizes an established research partnership with the supply chain division of a mid-sized, non-unionized U.S. based retailer, heretofore referred to as “Sigma.” Sigma employs approximately 4,800 non-supervisory employees in 24 fulfillment centers which are geographically dispersed across the United States. Within a given fulfillment center, the main job role is “picking,” whereby workers pick products, box them, and ship them based on a customer’s order. Each fulfillment center utilizes one of three technology systems to facilitate this work process: conveyors, carts, or robotics. Workers’ productivity, or how many orders a worker fulfills, as well as a workers’ “time off task,” is monitored via additional technology. Formative research and intervention development occurred in 2019 and 2020 and baseline recruitment of fulfillment centers began in July 2021. Given research team staffing constraints and Sigma’s interest in avoiding data collection during periods of high demand, there was a sequential roll-out of the intervention in three groups of fulfillment centers between July 2021 and July 2022. See page 8 for additional details on participant recruitment. Inclusion criteria. All fulfillment centers (N = 24) are assessed for eligibility for study inclusion. Exclusion criteria. Fulfillment centers are excluded from randomization if: there was a previously established union in the fulfillment center (N = 1), there are <15 employees at the site (N = 1), the site served as the pilot site (N = 1), the site shuts down during the study period (N = 1), or the site experiences a major change in leadership prior to or at the time of the baseline survey (N = 4). The research team and Sigma agreed to exclude the unionized site due to its distinctive nature and because the vast majority of sites did not have any unionized workers. Future research could explore how this participatory intervention can be implemented within a unionized context. See Fig 1 for the schedule of enrolment, intervention, and assessment. Randomization Following baseline survey administration, fulfillment centers are matched based on the main picking technology (conveyors, carts, or robotics) and size (small, medium, large, or very large) based on the number of workers within the fulfillment center. Within each technology and size group, each fulfillment center is randomized to either receive the intervention or to maintain operations as usual. Randomization occurred by randomly assigning numbers to be intervention or control and then randomly assigning them to study buildings. Site managers are then notified of their fulfillment center’s treatment assignment. Given the geographic distance between fulfillment centers, the likelihood of contamination between sites was considered minimal. PLOS ONE The Fulfillment Center Intervention Study PLOS ONE | https://doi.org/10.1371/journal.pone.0305334 July 18, 2024 4 / 18 Blinding Participants undergoing baseline measurement are unaware of arm allocation as randomization occurs after baseline. Due to the nature of the intervention, it will not be possible to blind participants throughout the data collection process. However, all recruitment materials will describe the study goals quite broadly (e.g., “The purpose of the study is to understand what Fig 1. Schedule of enrolment, intervention, and assessments. https://doi.org/10.1371/journal.pone.0305334.g001 PLOS ONE The Fulfillment Center Intervention Study PLOS ONE | https://doi.org/10.1371/journal.pone.0305334 July 18, 2024 5 / 18 it’s like to work at a fulfillment center in general and to understand how changes in the workplace affect your experience working at [Sigma]”) and will not mention the intervention. Additionally, those conducting final data analyses will be blinded to group allocation. Intervention The research team developed a new intervention, Health and Well-Being Committees (HaWCs), which is informed by existing workplace participatory programs and by best practices for engaging workers in safety initiatives and continuous improvement strategies, e.g., problem identification and definition, solution brainstorming, and solution implementation and testing [35,38,39]. The intervention was piloted in a fulfillment center between September 2020 and July 2021, after which the intervention was refined and finalized based on input from the pilot site. Fig 2 presents the intervention model with expected changes. HaWCs will be composed of 10–14 frontline workers and supervisors and led by a “colead” pair, comprised of one frontline worker and one supervisor. The dual managementworker leadership structure is designed to facilitate a joint problem-solving orientation with a focus on multiple stakeholder interests and mutual gain. Members of the HaWC are expected to be volunteers and to represent different departments, tenure, and social identities (e.g., gender and race). HaWC meetings will occur when associates and supervisors are “on the clock” and compensated for their time. HaWCs are designed to be a new formal voice channel where workers can submit concerns about the workplace environment pertaining to safety (e.g., physical hazards), the psychosocial environment (e.g., how workers feel about their treatment at work), and work organization (e.g., workflow, training opportunities, scheduling). HaWCs then will be charged with prioritizing concerns, designing, coordinating, and implementing solutions, and tracking outcomes. Following randomization, managers in intervention sites will meet with the research team to plan the intervention launch, identify possible co-leads, and plan recruitment of HaWC members. Co-leads will then participate in a multi-session training delivered by the research team where they will be trained in the continuous improvement strategies and facilitation skills. The intervention is comprised of four distinct stages designed to provide scaffolded support from the research team to the co-leads. The intervention stages include: the Start-up Phase, the Transition Phase, the Sustainability Phase, and the Maintenance Phase. The Start-up Phase (months 0–2 and meetings 1–4) consists of biweekly HaWC meetings during which the Fig 2. Health and Well-Being Committee participatory intervention model. https://doi.org/10.1371/journal.pone.0305334.g002 PLOS ONE The Fulfillment Center Intervention Study PLOS ONE | https://doi.org/10.1371/journal.pone.0305334 July 18, 2024 6 / 18 research team is highly involved in meeting planning, joint facilitation, and agenda setting. In the Transition Phase (months 2–4 and meetings 5–8), the research team continues to provide support while handing over responsibilities for meeting planning and facilitation to the coleads. During the Sustainability Phase (months 4–12), the co-leads are expected to fully run HaWC activities but consult with the research team approximately once every other month and on an informal basis as needed. The Maintenance Phase (months 12–30) begins after the quantitative evaluative period (T3) and consists of less frequent, but regular interaction between the research team and HaWC sites (approximately every 6 months) in order to evaluate whether and how the intervention is sustained. The Project Improvement Cycle begins with bi-weekly one-hour HaWC meeting. The cycle, shown in Fig 2, provides structure for meeting discussions. During these meetings, committee members hear suggestions from each other as well as suggestions that coworkers share via comment boxes or discuss directly with a HaWC member, prioritize work concerns, conduct a root cause analysis of the concern if deemed useful, brainstorm solutions, and develop and implement action plans. Following the implementation of an action plan, the improvement cycle will begin anew. The improvement cycle also provides flexibility for HaWCs to spend more or less time on a particular step, depending on the topic, allowing for a customized approach for addressing the needs of each particular site. A phased rollout was planned to be responsive to the firm’s busy periods and the research team’s capacity. Additionally, significant delays related to operational and staffing challenges in the wake of the COVID-19 slowed the timeline for the study launch. The intervention is still ongoing. Data collection and measures Table 1 provides an overview of data collection activities, aligned with overall study objectives. Survey measurement occurs at three time points: baseline (T1), 6 months (T2), and 12 months (T3). At each time point, all workers currently working in the fulfillment center are presented with an individualized invitation letter to complete a web-based survey via Qualtrics. Participants can access the questionnaire using a cell phone, research-team provided tablets, or desktop computers at the worksite. All participants will provide informed consent prior to participation. All participants are given the opportunity to participate in the survey while onthe-clock, but also have the option to participate outside of work. To promote participation, all individuals who complete the questionnaire are given a small incentive at each wave. Those who complete the questionnaire are also eligible to receive site-level raffles. In addition to the self-reported questionnaires, administrative data on worker characteristics and injuries and fulfillment centers-level characteristics are collected from Sigma databases. Table 1. Overview of study objectives and supporting research methods. Study Objective Supporting Research Method Evaluate the efficacy of the HaWC intervention and its effect on health outcomes and changes in the conditions of work Self-reported surveys from workers in HaWC and control sites (T1, T2, T3) Administrative data collection for all sites, including turnover rates, other changes in workplace policies or practices Conduct a process evaluation of key contextual factors that support effective and integrated intervention implementation and sustained engagement Tracking meetings and projects in HaWC sites (detailed tracking through T3, summaries after) Co-lead interviews in HaWC sites (every 6 months) Manager interviews in HaWC and control sites (T2, T3) Focus Groups in HaWC sites (T3) https://doi.org/10.1371/journal.pone.0305334.t001 PLOS ONE The Fulfillment Center Intervention Study PLOS ONE | https://doi.org/10.1371/journal.pone.0305334 July 18, 2024 7 / 18 Given the low-risk nature of the study, adverse events are unexpected. However, to ensure safety of study participants, the research team will proactively ask building managers whether concerns have arisen about the study. Should any concerns arise, participants will be able to contact the IRB and Human Resources department at Sigma. Outcome measures Table 2 presents a description of the outcomes measured in the study. All outcomes are measured at each of the three timepoints in both treatment and control sites. Primary outcome. The primary outcome is psychological distress, measured with the 6-item short form of the Kessler distress scale (K6) [40]. The K6 scale has been used widely in workplace studies as a short screener for discriminating between those who do and do not meet diagnostic criteria for a mental disorder. This scale has excellent internal consistency and reliability (Cronbach’s alpha = 0.89) [40]. Participants are asked the frequency of non-specific symptoms of psychological distress (feeling “nervous,” “hopeless,”, “restless or fidgety,” “so depressed that nothing could cheer you up,” “that everything was an effort,” and “worthless”) in the month prior to data collection. Response items are on a 5-point scale, ranging from (0) “none of the time” to (4) “all of the time”. Items are then summed to create an overall score between 0 and 24, with higher scores indicating higher levels of psychological distress and a score �13 suggesting severe mental illness [43]. Secondary outcomes. In addition to the primary outcome, the study will analyze the effect of treatment on several secondary outcomes (see Table 1). Psychological well-being is measured with a six-item scale comprised of three, two-item subscales assessing emotional vitality (e.g., waking up fresh and rested, how much energy, and vitality the participant had), sense of positive well-being (e.g., how happy, satisfied, or pleased the participant has been in their personal life, whether daily life has been full of things that were interesting), and emotional selfcontrol (e.g., whether the participant has been in firm control of their behavior, thoughts, emotions, or feelings, and whether the participant has been feeling emotionally stable and sure of Table 2. Overview of outcome measures. Outcome Source Description Primary Psychological distress Questionnaire Six-item short form of the Kessler distress scale [40]. Assesses the frequency of symptoms of psychological distress experienced in the last month. Secondary Psychological well-being Questionnaire Six items assessing emotional vitality, sense of positive well-being, and emotional self-control in the last month [41]. Work-related well-being Questionnaire Burnout: Two-item Maslach burnout scale [42]. Job satisfaction: One item rating satisfaction with the job from 0–10. Engagement: Two items assessing whether a worker’s mind is focused on their job and whether their job is boring. Psychosocial work environment Questionnaire Nine items from the Thriving from Work Questionnaire that assess perceptions of fair treatment, respect, belonging, purpose, support, work-life balance, fair pay, and job security. Voice environment Questionnaire Worker voice: Three items reporting on whether workers know who to talk to when they have an issue at work, whether they can make suggestions without getting into trouble, and whether leadership takes their concerns seriously. Conditions of work Questionnaire Job demands and control: Six items on decision authority, skill discretion, and psychological job demands. Safety climate: Six item safety climate scale and additional safety climate items specific to the COVID-19 pandemic. Self-reported health Questionnaire General Health: A single general item from SF-36. Musculoskeletal pain: A single modified item from the NordicQ. Sleep: A single item assessing sleep duration in the last 30 days from the Pittsburgh Sleep Quality Index. Injuries Questionnaire Administrative Data Questionnaire: Three items asking whether an injury was experienced, whether it was reported, and the reason for not reporting. Administrative data: Captures total injuries reported to Occupational Safety and Health Administration and number of recordable injuries per 100 workers, by site. https://doi.org/10.1371/journal.pone.0305334.t002 PLOS ONE The Fulfillment Center Intervention Study PLOS ONE | https://doi.org/10.1371/journal.pone.0305334 July 18, 2024 8 / 18 [28]. The study can produce exciting new data on fulfillment center workers’ health and wellbeing and the efficacy of this innovative participatory intervention. This will open important avenues for future research, including analysis on enterprise or organizational outcomes, such as absenteeism, turnover rates, and productivity. Lastly, the study will inform the development of participatory interventions in comparable industries where low-wage workers experience both social and physical hazardous working conditions. Supporting information S1 Checklist. 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