Despite controversy about paying research subjects, little is known about actual practices in the US, including what type of studies offer payment, to what type of subjects, and how amounts are determined.

To document current US practices regarding payment to research subjects.

The protocols and consent forms of 467 studies offering payment to research subjects approved by 11 IRBs across the US were reviewed to analyze how they describe and justify payment to subjects.

Money was offered in a wide variety of study types, from short term physiologic studies to large clinical trials of therapeutic interventions, to both patient (61%) and healthy (24.4%) subjects or both (14.6%). Dollar amounts varied widely and were infrequently explicitly described as based on time (19%) or procedures (12%). Unexplained variation in dollar amounts occurred in similar studies or in the same (multi-site) study at different sites, and for similar procedures across studies sometimes even within one site. Although the range was wide (5– 2000), total amounts were usually modest (overall median 155),andalmostalwaysdescribedintheconsentform(94.4%)andusuallyaspro-rated(73%).

BothpatientandhealthysubjectsareofferedpaymentinawidevarietyoftypesofresearchintheUSVariationinthedollaramountsofferedislargelyunexplained.