Interviews take many forms, some very informal, others more structured.
Unstuctured interviews are like a casual conversation. There are no set questions and the participant is given the opportunity to raise whatever topics he/she feels are relevant and about them in their own way. In this kind of interview much qualitative (i.e. descriptive) data is likely to be collected about how the person talks, when pauses occur in the conservation and well as what is said. Carl Rogers used this method in his person centred therapy as a means to help the client explore their own thoughts and feelings. During an unstructured interview an interviewee may take the interview in directions not anticipated at start (this would not happen in structured interview).
• Pro: Qualitative data: They are a rich source of (descriptive) data relating to what the interviewee themselves feel is important.
• Pro: It allows the researcher to discover points they may not have previously considered and may introduce new lines of enquiry, i.e. ask additional questions.
o Con: Lacks reliability as the interview cannot be repeated.
o Con: Different data will be collect from each participant so comparisons and analysis are difficult.
Structured (formal) interviews are like a job interview. There is a fixed, predetermined set of questions that are put to every subject in the same order and in the same way. The interviewer stays within their role and maintains social distance from the interviewee. Questions mat be open ended (e.g. “why do you enjoy listening to music?”), or have closed answers, that is a fixed choice of answers is offered (e.g. “What type of music do you enjoy? Jazz, Pop, Classical etc.”)
• Pro: Reliability: Because the situation is standardised results tend to be consistent.
• Pro: Quantitative data: Because the interview is usually aimed at gathering factual data that fits into predetermined categories it yields information that can easily be translated into numbers for the purpose of measurement.
o Con: Social desirability bias: Most people want to present themselves in the best possible light, so they may provide socially desirable rather than honest answers to personal questions.