Higher monetary incentives led to a lowered response rate in ambulatory patients: a randomized trial.
OBJECTIVE
Monetary incentives can increase response rate in patient surveys, but calibration of the optimal incentive level is required. Our aim was to assess the effect of different monetary incentives on response rates to calibrate the optimal monetary incentive for ambulatory patients.


METHODS
A patient-randomized trial was performed in which targeted individuals received different gift vouchers (€5.00, €7.50, €10.00, and €12.50) on completion of a survey and interview. Eligible patients (diagnosed type 2 diabetes, over 18 years) were recruited from primary care practices.


RESULTS
The response rate for the €12.50 incentive was lower compared with both the €7.50 and the €10.00 incentive [odds ratio (OR) = 0.60 and OR = 0.58]. A nonlinear model yield a better fit than a linear model. Within the observed range of incentive levels, an overall decrease in response rate was found.


CONCLUSIONS
High monetary incentives are not only inefficient but also less effective.
Radboud Institute for Health Sciences, Department of IQ healthcare, Radboud university medical center, Nijmegen, The Netherlands. Electronic address: jan.koetsenruijter@radboudumc.nl.
Jan
J
Koetsenruijter
Radboud Institute for Health Sciences, Department of IQ healthcare, Radboud university medical center, Nijmegen, The Netherlands.
Jan
J
van Lieshout
Radboud Institute for Health Sciences, Department of IQ healthcare, Radboud university medical center, Nijmegen, The Netherlands.
Michel
M
Wensing
D000553:Ambulatory Care; D006801:Humans; D007407:Interviews as Topic; D009042:Motivation; D010358:Patient Participation / Q000191:economics* / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires / Q000191:economics*
Ambulatory patients; Deprivation; Diminishing returns; Incentives; Monetary incentive; Response rate; Survey