This article reports the results of a meta-analysis of experimental studies which have examined ten different factors felt to influence response rates to mail surveys. The form of meta-analysis used clearly defines the individual impact of each of the factors examined. Results indicate that prenotification and follow-ups increase the response rate, as does the type of outgoing postage used. Furthermore, studies sponsored by a university receive greater returns. Increases in the size of the monetary incentive used appear to have decreasing marginal gains. Finally, some evidence exists to suggest that the color of the questionnaire influences response rate.