Eileen Morrow, NIHR Doctoral Clinical Academic Research Fellow at NDORMS said the research community ‘must acknowledge the problem and dedicate resources to testing and implementing safeguards .. to ensure that the data guiding clinical care reflect the real patient voice.’
Imposter participants are individuals who provide deceptive or inaccurate data in order to take part in health research or automated computer ‘bots’ which mimic human behaviour and responses.
The issue has grown in recent years as online recruitment has become central to modern healthcare research and can impact all types of studies, from surveys to randomised controlled trials.
The motivations of imposter participants remain unknown, explained Eileen who conducted the study with colleagues from NDORMS. Although some reports suggest that monetary benefit is a driver, not all studies offer financial incentives, so other motives, such as boredom, curiosity, or even an ideological intent to disrupt research, may also play a role.
Yet their impact is demonstrable. A 2025 review showed that 18 of 23 studies which looked for imposter participants in their data sets, found them, with rates ranging from 3% to a high of 94%.
The advice from the study, published in The BMJ, is that researchers should routinely integrate imposter participant detection and prevention into online research, while giving consideration to the potential impact on their study population.
Common safeguards include identity verification procedures or CAPTCHA tests (asking participants to complete a task such as to read and type distorted letters).
At a minimum, studies should transparently report which safeguards were used and acknowledge their limitations, and journals should encourage consistent and transparent reporting of these safeguards.
Funders and institutions should also invest in infrastructure and training to help researchers keep pace with evolving tactics, while clinicians and policymakers should interpret online recruitment with caution when no mention is made of imposter participant prevention.
Eileen concludes: ‘Imposter participants are more than a nuisance; they are a systemic threat to health research. Their impact is demonstrable and their detection inconsistent. If left unaddressed, they risk undermining the integrity of health research and the decisions built upon it.’