Non-car owners have other worries which if raised with car owners may modify their attitudes. Reconcile differences in lifelike way. Not so useful for sensitive issues, detailed attitudes, or complex decision making processes - better to use depth interviews. Interviewer guided by aide memoire, not structured questionnaire. Must give info, otherwise respondent wondering what is researcher up to.
Interviewer analyses responses in terms of research.
Record, analyse tapes, remember gestures, expression, body language. Framework develops out of data, not fixed structure in which data must be pigeon- holed, as in quant. Represent heterogeneity of pop. Sometimes problems e.g. gatekeeper. Other bias, e.g. middle class respondents living in middle class areas, more chance than if living in mixed areas.