Step 5: Attach a cover letter to the questionnaire that reiterates the purpose and the importance of the questionnaire and describes the incentives and confidentiality policies you have established.

When the participant receives the questionnaire, he or she should be reminded of its purpose and importance in a cover letter. Even if participants will be completing the questionnaire on-site, the information should be presented in writing so that participants can refer to it. It should include the information that was in the notification letter, plus additional information such as:

• The incentive, if any, being offered.
  
• Ways in which confidentiality is being protected.
  
• Contact information for questions.

An example of a cover letter appears in the Scenario section of this module. If the cover letter and questionnaire are sent by mail, the packet should include a prepaid return envelope.

For off-site delivery, the timing of sending the cover letter and questionnaire can be important. Experience shows that people are less likely to respond to a questionnaire that arrives near a holiday period or weekend (i.e., a Friday or Monday). Timing a questionnaire to arrive in the middle of the workweek seems to be more effective.