People who are paid to take part in research studies may be more likely to lie about their eligibility than those who aren't paid, a new study finds.
It included nearly 2 300 people who were surveyed on whether they're received a recent flu shot. One group of participants was told that their eligibility to take part in the survey didn't depend on whether or not they'd had a flu shot. This was the control group.
Undermining of integrity and results
But other groups were offered $5 (±R72), $10 (±R144) or $20 (±R287) for taking part in the survey and were told they were eligible only if they had or had not received a recent flu shot.
In the control group, 52% of respondents said they'd had a recent flu shot. But among those who were told that their survey eligibility depended on recent flu vaccination and received payments of $5, $10 or $20, rates of participants who said they'd had a flu shot were 63.1%, 62.8% and 62.1%, respectively.
Rates among those who were told that their eligibility depended on having not received a recent flu vaccination were 46.5% at $5, 41.8% at $10, and 46.7% at $20.
The only differences between the groups in the study were their eligibility criteria and payment amounts, so the differences in their self-reported vaccination rates were due to lying, the University of Pennsylvania researchers said.
They calculated that between 10.5 and nearly 23% of participants lied about their eligibility to participate.
"This type of behaviour not only undermines a study's integrity and its results, but in a study with eligibility criteria that are intended to protect participants, it also has the potential to put participants at risk," first author Holly Fernandez Lynch said in a university news release. She is an assistant professor of medical ethics and health policy at the Perelman School of Medicine.
Rates of lying unconnected to amount
Payment is often used to get people to enrol in studies, but there has been little research on whether and to what extent people will lie about their eligibility or other aspects of participation to get paid.
"Rather than relying on self-reporting by participants, investigators should use objective metrics whenever possible," said study senior author Emily Largent, an assistant professor of medical ethics and health policy.
"The best response to our findings is not necessarily to reduce or eliminate payment offers for participation. Payment can help boost legitimate enrolment; in addition, investigators may owe payment as compensation for the time, effort, and burden that participants assume by joining the study," she added.
The researchers did note that the rates of lying seemed unconnected to the amount of payment offered.
"This suggests that keeping payments low will not necessarily prevent deception," said study co-author Dr Steven Joffe, chief of the Medical Ethics division. "It also suggests that higher payments may encourage recruitment without posing a greater risk to the study's integrity."
The findings were published recently in JAMA Network Open.
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