The rising challenge of imposter participants in health research
Health studies increasingly rely on online recruitment to reach diverse populations quickly and at scale. But this shift has brought a troubling problem to the fore: imposter participants. In a commentary published in The BMJ, Eileen Morrow and colleagues from the University of Oxford argue that deceptive participants — or automated bots that mimic human responses — threaten the integrity of health research and, by extension, the policies and clinical decisions built on it.
Imposter participants are individuals who provide deceptive or inaccurate data to join studies, sabotaging findings, or machines that simulate human responses to study prompts. The issue is not theoretical: a 2025 review found that 18 of 23 studies seeking imposter participants detected them, with reported prevalence ranging from 3% to 94% depending on the study design and detection methods. The authors emphasize that the problem affects a spectrum of research—from surveys to randomized controlled trials—and the consequences can ripple into misinformed clinical care and misguided health policy.
Why the motives remain unclear and why impact matters
One of the key challenges highlighted by Morrow and colleagues is the unpredictability of imposter motivations. While monetary gain is suggested in some cases, many studies do not offer financial incentives, pointing to alternative drivers such as boredom, curiosity, or even deliberate disruption of research efforts. Regardless of motive, the practical impact is tangible: distorted data can skew effect estimates, misrepresent patient experiences, and undermine the external validity of findings.
The authors stress that imposter participation is not a minor nuisance but a “systemic threat to health research.” In an era where online recruitment underpins everything from large-scale surveys to multicenter trials, the integrity of data becomes a prerequisite for reliable evidence. When the “real patient voice” is muddied by imposters, clinicians and policymakers may base decisions on biased or fraudulent information, potentially compromising patient safety and resource allocation.
Practical safeguards researchers can adopt now
To counter this threat, the BMJ authors advocate for routine integration of imposter detection and prevention into online research workflows. They call for transparent reporting of safeguards used, as well as honest acknowledgement of their limitations. Journal editors and funders can play a pivotal role by standardizing reporting practices and supporting infrastructure to defend data quality.
Among common safeguards, identity verification procedures and CAPTCHA-like tests are frequently used. These tools aim to ensure that respondents are real people rather than automated agents or fraudulent participants. However, the authors cautions that such measures are not panaceas and may erase or discourage legitimate participants if not implemented thoughtfully. They emphasize balancing rigor with accessibility, so diverse populations are not inadvertently excluded.
Strategic actions for researchers, funders, and journals
For researchers, the imperative is to embed detection and prevention into study protocols from the outset, including during the planning phase of online recruitment. Transparent reporting should detail which safeguards were used, how they performed, and what limitations were observed. This transparency enables readers, clinicians, and policymakers to interpret results with a clearer understanding of potential data quality issues.
Funders and institutions are urged to invest in robust infrastructure, training, and ongoing updates to counter evolving tactics used by imposter participants. The pace of innovation in recruitment and data collection means researchers need timely support to stay ahead of fraudulent methods. Clinicians and policymakers must remain cautious when interpreting online-recruited evidence if explicit protections against imposter participation are not documented.
Looking ahead: safeguarding the integrity of health research
The authors conclude with a clear warning: imposter participants are more than a nuisance; they are a systemic threat to health research. As online recruitment underpins a growing share of evidence generation, the research community must rise to the challenge with validated safeguards, transparent reporting, and sustained investment in defense mechanisms. By doing so, the field can protect the integrity of data that informs patient care, improves trial design, and shapes health policy for the better.
