Telephone interview is a quick and less expensive way to get feedback from users. It is however relevant only if you do not plan to ask for more than 15 minutes. It is good for b-2-b surveys. Telephone interviews conducted from a specially equipped call center, where the interview procedures are controlled by computer, and interviews are regularly tapped.
Correct sampling is crucial to the success of telephone survey. And it is not easy, given that many respondents have both mobile and fixed phones, and some are mobile only. Learn how we do it.