In-Depth Interviews: Advantages, Disadvantages, and Best Practices

Challenges in Interviewing Marginalized Groups

A clear case involves particularly marginalized groups: criminals, prostitutes, drug addicts, people with stigmatized diseases, people experiencing homelessness, etc. Even when the researcher has some notion about certain places where they can locate some of these potential respondents, they must not forget the high degree of volatility or mobility of these groups. If we can establish a good relationship with any of them, we may be on the right track. Through their influence, we can get new elements for our sample. This is known as the "snowball effect." The first interviewees give us information that will permit the location of other individuals likely to swell our "sample." And these, in turn, provide us with contact with others, and so on. The saturation criterion tells us when to stop the selection of that profile or redesign the sample interviewed. In these samples, it is also often essential to go where they are, with few exceptions.

Importantly, researchers will also have to assess the relevance of the information potential of future interviewees, as well as their availability and ability to communicate information with some precision.

Fieldwork and Sample Size Considerations

In qualitative research, it is usual for the investigator to conduct fieldwork. However, there are cases where the sample size makes it essential to include other interviewers on the team. The sample size may require, in certain contexts, employing other professionals or companies that are responsible for contacts according to the types or profiles designed. But this may lead to a somewhat biased sample and even sometimes having to deal with professional interviewees.

All the constraints we've been pointing out contribute to the preparation of the final design of the study, which, obviously, will put an end to the fieldwork.

Advantages and Disadvantages of In-Depth Interviews

To sum up, let's discuss the in-depth interview in a comparative perspective with other social research techniques.

In-Depth Interview Versus Structured Interview (Survey)

Advantages:

• The interviewee becomes the protagonist of the research practice. When they accept their role, it is within the framework of a conversation model that is more familiar than the structure of a questionnaire with closed response categories. Certain population groups are not prepared for the latter.
• Information produced by in-depth interviews is much richer, reflecting the spontaneous perception and interpretation of the interviewee. This contrasts with the rigidity of the answers given on a questionnaire to confirm the definition of the research problem at the outset.
• The figure of the interviewer is equated with the investigator. They must have extensive knowledge of the subject to successfully face an interview situation in which few things are predetermined. Their role is revalued against the pollster who systematically repeats the same pattern, without having virtually any creative role in the interaction.
• The flexibility of the instrument allows for adding new paths and perspectives of analysis in a design that is simply outlined in the draft. This is a particularly suitable design to further the comprehensive process.
• Its heuristic potential places it in a privileged place as a practice that "opens doors" or is exploratory. It permits refining other quantitative instruments, such as the questionnaire itself.

Disadvantages:

• The disadvantages of using open interviews clearly point to two parameters from the quantitative perspective when applying the criteria of the scientific method of natural science itself to this kind of practice. The criticism focuses primarily on the difficulty of controlling the validity and reliability of the instrument and, therefore, ensuring comparability and inference (see Chapter 1).
• Not enough has been said about the influence of the researcher/interviewer as co-author of the interview (biases and notions taken for granted).

At this point in the chapter, readers will wonder what the procedure is to convert the materials produced by the interviews into a report that sheds light on the research problem. How should it be put into practice?