Introduction Research supports the efficacy of both a remedial consent procedure (corrected feedback (CF)) and a motivational consent procedure (incentives) for improving recall of informed consent to research. Although these strategies were statistically superior to standard consent, effects were modest and not clinically significant. This study examines a combined incentivised consent and CF procedure that simplifies the cognitive task and increases motivation to learn consent information.

Methods We randomly assigned 104 individuals consenting to an unrelated host study to a consent as usual (CAU) condition (n=52) or an incentivised CF (ICF) condition (n=52). All participants were told they would be quizzed on their consent recall following their baseline assessment and at 4 monthly follow-ups. ICF participants were also informed that they would earn $5 for each correct answer and receive CF as needed.

Results Quiz scores in the two conditions did not differ at the first administration (p=0.39, d=0.2); however, ICF scores were significantly higher at each subsequent administration (second: p=0.003, Cohen's d=0.6; third: p<0.0001, d=1.4; fourth: p<0.0001, d=1.6; fifth: p<0.0001, d=1.8).

Conclusions The ICF procedure increased consent recall from 72% to 83%, compared with the CAU condition in which recall decreased from 69% to 59%. This supports the statistical and clinical utility of a combined remedial and motivational consent procedure for enhancing recall of study information and human research protections.