Skip to main content

Table 4 Effect of incentives

From: Non-randomised evaluations of strategies to increase participant retention in randomised controlled trials: a systematic review

Study ID Study design Comparator Intervention Difference in response rate (primary end point) Difference in response rate (secondary end point)
Brealey 2007 [35] Historical control study design No incentive (the first 105 patients did not receive the £5 incentive) The subsequent 442 patients received unconditional direct payment of £5 for the completion and return of questionnaires The response rate (12 months after randomisation) following reminders for the historical controls was 78.1% (82 of 105) compared with 88.0% (389 of 442) for those patients who received the £5 payment (diff = 9.9%, 95% CI 2.3 to 19.1%). No secondary end point reported
Rodgers 2016 [36] Prospective cohort study In-person cash incentive for the first 111 participants The subsequent 358 participants were given reloadable bank card for incentive payments Retention rates among the card-paid participants at 6 months was 80% vs. 68% cash-paid Retention rates among the card-paid participants at 12 months was 72% vs. 66% cash-paid