Which Letter Worked Best?

This note reports the results of a study which applied direct marketing techniques to the writing and presentation of a covering letter for a mail survey of the general public. The vehicle for this research was the 1993 International Social Survey Programme (ISSP) survey on attitudes to the environment. Nine versions of the covering letters were produced (examples of these are reproduced in the Appendix). Eight letters were based on two different appeals, an altruistic appeal and an egoistic appeal. Within each appeal were four versions of the covering letter, differing in terms of complexity, tone, and the presence or absence of graphics. The ninth letter was written by a direct marketing consultant on the basis of a brief provided. The results of this study suggest that the content and appearance of covering letters can influence the response rate for mail surveys, but that the effect may depend on the type of appeal and on the way in which it is conveyed. For mail survey practitioners, the implication is that they need to tailor the appeal they use and its execution to the characteristics and expectations of the target population. This would be no surprise to direct marketers. They have known for years that, after the medium and the list, the two most important leverage points in direct marketing are the offer (What's in it for me?) and the format. The same, it seems, applies to mail survey covering letters