This paper describes a five-step procedure for meta-analysis. Especially important was the contacting of authors of prior papers. This was done primarily to improve the accuracy of the coding; it also helped to identify unpublished research and to supply missing information. Application of the five-step procedure to the issue of return postage in mail surveys yielded significantly more papers and produced more definitive conclusions than those derived from traditional reviews. This meta-analysis indicated that business reply postage is seldom cost effective because first class postage yields an additional 9% return. Business reply rates were lower than for other first class postage in each of the 20 comparisons.
Postprint version. This is a pre-copy-editing author-produced PDF of an article published in Public Opinion Quarterly, Volume 51, Issue 2, Summer 1987, pages 233-248, following peer review.