Differential response on pre- and post-disclosed committed inducements in a face to face interview

Inducements of different forms and at different stages are used for motivating people to participate in human subject research. Although it is accepted that inducements, in general, play a positive role in increasing participation rate, there are exceptions. Inducements may contaminate the quality of research findings or may even reduce response rate in some circumstances. If the research project is purely for public goods, the researcher does not have any intention of personal gain, and that message is clearly conveyed to the prospective respondents, a material inducement may not be needed. Under such a situation, peoples' altruistic behavior takes precedence over psychological egoism.