Key points are not available for this paper at this time.
A study involving 2,416 randomly selected magazine readers indicated that response rates to mail questionnaires were significantly increased by the use of 25¢ premiums, but not by the use of a free-book premium or a free-book reward for responding. Response rates over time showed a very significant linear trend with an additional smaller cubic component. A complex significant (cubic) relationship between speed of response and favorability of expressed opinions reinforced conclusions that the broadest spectrum of opinions is obtained best by maximizing response rates.
Goodstadt et al. (Mon,) studied this question.