The results of this experimental study suggest that advance correspondence produces a higher response rate, but at a higher cost per usable return, than using no advance correspondence. Two forms of advance correspondence, postcard and letter, produced approximately equal response rates but the advance postcard had a lower cost per usable return. The findings are discussed in the context of mean
... [Show full abstract] square error to illustrate that the researcher ordinarily must be concerned about both response rate and number of returns when designing a survey.