This paper reports on the link between a well-defined measure of response burden and response rates among all (uncommitted) and pre-recruited respondents. We show within the limits of our sample of 68 survey waves (including pre-tests; resulting from 35 studies) that the response burden impact is mediated by the level of the commitment of the respondents and the presence of a monetary incentive. This is the first time that a research group provides a response rate forecasting model for its own work and for others to adopt, test and adapt.