Which type of questionnaire is mailed to respondents and then returned by post?

• A. Self-completion questionnaires
• B. Postal questionnaires
• C. Structured interview
• D. Telephone questionnaires

Answer: (B)

The main idea here is how the questionnaire is delivered and returned. A postal questionnaire is sent to respondents through the mail and then returned by post once they’ve filled it in. This method lets researchers reach a wide area at relatively low cost and without an interviewer present, which can reduce interviewer influence and encourage frank answers. However, it often faces lower response rates and slower data collection.

In contrast, a self-completion questionnaire can be completed by the respondent in various ways, not necessarily by post. A structured interview involves an interviewer asking fixed questions to the respondent, usually in person (or by phone), so it isn’t mailed. Telephone questionnaires are conducted over the phone, also not mailed.

So the description fits postal questionnaires because the process specifically involves mailing the questionnaire to respondents and receiving it back by post.