In-depth interviews are also referred to as IDIs or one-on-ones. They are a form of qualitative research used to uncover beliefs, behaviors and motivations of respondents. An in-depth interview is traditionally conducted in person or over the telephone with the researcher asking questions of an individual respondent.
In-depths are best suited for discussions that require a highly detailed exploration of an issue. Depending on the subject matter and context, the interviews last from 30 to 60 minutes each. In-depth interviews can take place anywhere the respondents are — at work, home, a public location, a research facility or by telephone. This method of gathering feedback can be particularly useful in situations in which the desired research respondents have limited time availability or are spread out geographically.
Although IDIs are designed to focus on the issues being researched, the actual interviews are somewhat flexible in the sense that respondents may direct the discussion to areas that are significant to them or to important ideas that the researcher had not originally considered. In these situations, it is important for the interviewer to balance participants' desire to talk about matters that they feel are important with the need to cover all aspects of the research topic. Additionally, the researcher needs to thoroughly understand the client's needs to know when to pursue a respondent's off-topic comment.
When conducting in-depth interviews, it is imperative that respondents be treated respectfully throughout the research process. It is important to schedule the interview at a time and place that are convenient for the participant. When setting up the IDI, the researcher should be forthright about the subject matter that will be covered as well as the length of time that the interview will take.