Step 6: For questionnaires administered off-site, be prepared to follow up with participants who do not respond.

As discussed earlier (Step 1), a disadvantage of off-site questionnaires is that some participants fail to respond. Nonresponse can be minimized by developing a system for contacting nonrespondents and reminding them why the questionnaire is important. Based on Dillman (2000), a set of guidelines for a follow-up system is as follows:

1. One week after participants receive the questionnaire, send a short reminder to nonrespondents stating when and why they received the questionnaire, thanking them if they already have returned it, and offering to resend the questionnaire if necessary.

2. Three weeks after the initial mailing, send nonrespondents another copy of the questionnaire with a letter reinforcing the information in the original cover letter. The letter should emphasize the importance of the questionnaire and note the usefulness of the responses already received. An extra incentive is not appropriate at this point because it would reward a tardy response. (A sample follow-up letter appears in the Scenario.)

3. Six or seven weeks after the initial mailing, send the remaining nonrespondents a final questionnaire copy and letter. This letter should emphasize that the deadline is imminent and that hearing from all participants is essential to the study.

The above guidelines can be modified according to circumstances. For example, if an evaluation is relatively small (say fewer than 100 participants), it may be affordable to contact nonrespondents by phone instead of in writing. Also, the timeline of certain program evaluations may allow only a short follow-up process.