I am currently in the preparation of a mail survey of readers of a journal/magazine. In order to motivate for a high participation rate in the survey an incentive should be reflected in a higher response rate.
In principle, I have to options but I don't know which one is better:
(a) To send a small present enclosed in the envelope with the survey questionnaire.
OR (b) To invite potential respondents to take part n a competition where they have the chance to win one of some gifts. Any tips and ideas?