Key points are not available for this paper at this time.
Thomas A. Heberlein, Robert Baumgartner, Factors Affecting Response Rates to Mailed Questionnaires: A Quantitative Analysis of the Published Literature, American Sociological Review, Vol. 43, No. 4 (Aug., 1978), pp. 447-462
Heberlein et al. (1978) studied this question.