What is the chief advantage of using each of the following contact methods: mail questionnaire, telephone interview, and personal interview?
Answer: The chief advantage of each contact method mentioned is (1) mail questionnaire the best way to reach people who would not give personal interviews or whose responses might be biased or distorted by the interviews, (2) telephone interviews the best method for gathering information quickly and the interviewer is also able to clarify questions if respondents do not understand them, and (3) personal interview the most versatile method because they can ask more questions and record additional observations about the respondent.