The science of being a study participant: FEM-PrEP participants’ explanations for overreporting adherence to the study pills and for the whereabouts of unused pills

Self-reported adherence in the FEM-PrEP study was high, yet in blood tests, drug concentrations revealed limited pill use. Participants primarily overreported adherence out of concern they would be terminated from FEM-PrEP for nonadherence and lose the study’s health care benefits. Findings suggest women want access to better health care. Efforts to improve self-reporting should identify alternative methods for creating supportive environments for reporting actual adherence.