A Quick Zoom Call at Recruitment Keeps Study Participants Engaged to the End

Online research has a fraud problem, and it is getting worse. Programmable bots, professional survey-farm operators, ineligible impostors, and simply careless respondents now threaten the integrity of behavioral studies that once seemed safe from contamination. A new study published in Behavior Research Methods by Andrea L. Howard and Johanna Peetz of Carleton University offers a strikingly low-tech answer: meet your participants face to face on a video call before you let them into the study. The researchers found that a single videoconference eligibility verification session, conducted one participant at a time over Zoom, produced dramatically better retention in a longitudinal intervention study than passive online screening alone, with more than 90 percent of videoconference-verified participants completing every wave of the study.

The context for this work is the ongoing crisis of data quality in internet-based research. Crowdsourcing platforms and open online surveys have made it possible to recruit thousands of participants quickly and cheaply, but that convenience has attracted a shadow economy of fraudulent respondents. Recent reviews of online studies published in 2022 found that many researchers still lack systematic practices for evaluating data quality, and a growing literature documents the scale of the problem: survey bots that mimic human responding, workers who misrepresent their identities or eligibility, and participants who speed through questionnaires without reading a single item. For longitudinal studies, which depend on the same people returning again and again over weeks or months, the stakes are even higher, because every fraudulent or disengaged recruit who drops out represents wasted resources and statistical power.

Howard and Peetz took advantage of a natural experiment embedded in their own research program. The study drew on existing data from a longitudinal financial intervention study of Canadian young adult women, with a total sample of 1,257 participants who had been recruited through three different streams. The first stream involved active videoconference verification: prospective participants were invited to a one-on-one Zoom meeting in which a researcher confirmed their identity and eligibility before enrollment. The second stream used passive screening, in which respondents were considered eligible if they possessed valid e-mail addresses and their contact information was not definitively fraudulent. The third stream consisted of pre-screened members of Prolific.com, a commercial participant platform that maintains its own vetting procedures. Because the researchers preregistered their hypotheses and analysis plan before compiling the data, the comparison was planned rather than post hoc, lending credibility to the findings.

The methodological design was unusually thorough. The researchers evaluated participants on seven distinct measures of retention, including whether they initiated the study, whether they completed the first wave, and whether they remained enrolled through subsequent waves over the course of the intervention. They also assessed six measures of engagement with the study tasks, including the time participants took to complete surveys, their interaction with the intervention activities, and indicators of honest responding such as attention checks. This dual focus matters because retention and engagement are conceptually distinct: a participant can show up for every session while clicking through the tasks mindlessly, or engage deeply once but then vanish. By separating these outcomes, the study could pinpoint exactly what videoconference verification does and does not buy a researcher.

The results on retention were unambiguous. Participants who had been verified over videoconference showed better rates of study initiation than those recruited through either passive screening or the commercial platform, and their longitudinal retention was superior as well. More than 90 percent of the videoconference-verified group completed all study waves, a remarkable figure for a multi-wave intervention study, where attrition rates of 30 to 50 percent are common in the literature. The passive screening stream, by contrast, almost certainly retained some fraudulent respondents among those who never responded to invitations or failed to show up for their Zoom appointments, since the initial e-mail screening was deliberately inclusive and only excluded contacts whose information was definitively fake.

Yet the engagement findings complicate the story. On measures of engagement, the three recruitment streams looked largely the same. The researchers found no meaningful differences in time to survey completion, in how participants engaged with the intervention activities, or in indicators of honest responding. In other words, videoconference verification did not produce participants who worked faster, tried harder on the intervention tasks, or answered more honestly once they were in the study. What it produced was participants who stayed. The distinction is important for researchers deciding how to allocate limited screening resources: if the primary threat to a study is attrition rather than careless responding, verification appears to be an efficient tool, but it is not a substitute for in-study attention checks and engagement measures.

The psychological mechanisms behind this effect are worth considering. One plausible explanation involves the sunk-cost dynamic documented in decades of behavioral economics research: participants who have invested effort in a Zoom appointment, shown their face to a researcher, and established a personal connection may feel more committed to seeing the study through. A brief face-to-face interaction transforms an anonymous transaction into a social relationship, and social obligations are notoriously harder to abandon than click-through commitments. There may also be a self-selection component, since people willing to schedule and attend a video call are likely those with more stable schedules and greater intrinsic motivation, meaning the verification session functions partly as a filter for reliable participants rather than only as a commitment device.

The study also speaks to a live debate about who bears responsibility for data quality. Some methodologists have argued that the burden for high-quality online data collection lies with researchers rather than recruitment platforms, and this study supports that view in a specific way: even participants drawn from a pre-screened commercial platform did not match the retention of videoconference-verified recruits, suggesting that platform-level vetting does not capture the commitment benefits of personal contact. At the same time, the authors note practical constraints. Prolific imposes maximum completion times once a survey begins, and videoconference verification requires researcher time that scales linearly with sample size, making it most practical for longitudinal intervention studies where each participant’s continued presence is worth a substantial investment. For massive cross-sectional surveys, the calculus may differ.

Limitations deserve honest acknowledgment. The sample consisted of Canadian young adult women recruited for a financial literacy intervention, so generalization to other populations, topics, and study designs remains to be demonstrated. The comparison across recruitment streams was not a randomized experiment at the level of the individual participant, since people self-selected into their recruitment pathways, and the researchers used existing data from a study originally conducted for a contract with the Financial Consumer Agency of Canada, which was not involved in the present analysis. The preregistration also contained a minor error about the recruitment start date, which the authors transparently corrected. None of these caveats undermines the central finding, but they frame it as strong evidence from a quasi-experimental comparison rather than definitive causal proof.

For the research community, the takeaway is both simple and consequential: engagement, or at least the kind that matters most for longitudinal research, begins at recruitment. A five-minute video call before enrollment appears to select and commit participants in ways that e-mail screening and platform pre-screening cannot, cutting attrition to levels that would make most longitudinal researchers envious. As fraudulent respondents grow more sophisticated and artificial intelligence makes automated survey-taking easier than ever, methods that exploit genuinely human signals, like showing up on camera and talking to a real person, may prove among the most robust defenses available. The study’s data and analysis code are publicly available on the Open Science Framework, allowing other researchers to scrutinize and build on the approach. In an era when the cheapest research methods are also the most vulnerable to contamination, Howard and Peetz’s results suggest that a modest investment of researcher time at the front door pays dividends all the way through the final wave of data collection.

Subject of Research: Comparing videoconference eligibility verification with passive online screening for participant retention and engagement in longitudinal online research

Article Title: Engagement begins at recruitment: Comparing videoconference verification to passive online screening for participant retention and study engagement

Article References: Engagement begins at recruitment: Comparing videoconference verification to passive online screening for participant retention and study engagement. (n.d.). https://doi.org/10.3758/s13428-026-03194-8

Image Credits: AI Generated

DOI: 10.3758/s13428-026-03194-8

Keywords: online research, participant retention, videoconference verification, survey bots, data quality, longitudinal studies, Prolific, participant engagement, recruitment screening, Behavior Research Methods, attrition, research methods