Questionnaires - are self-completed and ask respondents to provide answers to pre-set questions. Can be given to people by post, in person, email or completed on the spot.
Closed-Ended Questions - respondent chooses from pre-set answers (yes, no, maybe).
Open-Ended Questions - respondent is free to answer however they want, in their own words.
Advantages and Disadvantages
Practical - quick and cheap to produce. No need to recruit and train interviewers. Easy to quantify.
Ethical - Few ethical issues. Respondents choose whether they wish to complete the questionnaire. Often confidental.
Reliability - Can be repeated as the questionnaires can be identical…