Questionnaires can be mailed out to a sample of the population, enabling the researcher to connect with a wide range of people. The questionnaire is typically sent in a packet that contains a cover sheet, introducing the research being conducting, and a pre-paid return envelope for the responses. While the response rate is typically lower than other forms of questionnaires, this can be improved with reminders and incentives. There are examples of government run, compulsory mail out questionnaires, such as the Australian Census, which collect valuable population data.
- Sample is not limited to access to technology such as phones or Internet
- Participants are able to think about their responses
- No interviewer present helps control for interviewer effect on participants responses.
- Cost is lower than telephone questionnaires
- Can have a low response rate if people view the questionnaire as junk mail
- Questions cannot be probed or explained
- Participants may return incomplete surveys
- Possibility of a self-selection bias