1 November 2023 857 words, 4 min. read

The 5 types of qualitative interviews and their applications

By Pierre-Nicolas Schwab PhD in marketing, director of IntoTheMinds
If you plan to conduct qualitative interviews (e.g., for market research), you need to think carefully about which variant best suits your project. In this article, we'll look at the different variants and explain when to use them.

Qualitative interviews belong to the family of techniques known as “qualitative.” There are many distinct types of qualitative interviews, which are reviewed in this article. You will also find concrete examples of applications for your market research.

Have your qualitative research conducted by a reputable institute

Before getting to the heart of the matter, let’s take a quick look at the purpose of qualitative interviews.

Qualitative interviews are used as an exploratory technique in various contexts: market researchcustomer satisfaction research, audits of all kinds, sociological studies, etc. They are generally based on and interview guide.

 A qualitative interview aims to gain a detailed understanding of the factors that influence the behavior of an individual, a group, or an organization. This detailed understanding enables us to construct hypotheses that can then be evaluated quantitatively.

In their book “Méthodes des sciences sociales,”  Pinto et Grawitz (1967) distinguish five levels of interviewing, depending on the degree of freedom left to the interviewee.

Level 1: the qualitative “clinical” interview

Their first level, known as “clinical,” authorizes a maximum degree of freedom, allowing us to penetrate the psychological arcana of the subject, considered strictly speaking as a patient.

When to use it?

This type of interview is ideal for tackling a complex subject from a blank sheet of paper. The freedom given to the respondent is ideal for grasping a problem’s facets. This “clinical” approach is of interest in sociological and psychological research and marketing. The broadest possible approach to clinical research is also a clear advantage in developing disruptive products. Bringing disruptive products to the market requires an incredibly open approach.

Points to bear in mind

There are several points to bear in mind:

  • The difficulty of the exercise: clinical interviews are, by definition, conducted without an interview guide. You need to be accustomed to this type of method.
  • The interviewer’s bias: the interviewer must be careful not to project their biases or “guide” the respondent. It’s a coaching exercise in which the respondent decides which direction his discourse can take.

Level 2: the in-depth interview

The second level, the “in-depth interview” or “free interview, “reduces the degree of freedom by defining an interview theme.

When should it be used?

This type of qualitative interview is ideal for researching the complete use of a product or service and developing a new solution. The theme imposed forces the respondent to explore all facets of the subject. The in-depth interview is, therefore, ideal for exploring different avenues, discovering new ones, and formulating working hypotheses that can be verified later (with a survey, for example).

Points to bear in mind

An interview guide is optional for this type of interview, but the interviewer still needs to be able to bounce back and lead the discussion. In this respect, any bias he might bring to the discussion must be carefully monitored.


Level 3: the focused interview

The third level is the “focused interview” or “guided interview,” in which several themes are defined. The interviewer’s attitude is more directive than in the in-depth interview.

When to use it?

Focused interviewing is perfectly suited to satisfaction surveys and market research concerning an existing product or one already available at the prototype stage. In this type of research, you need to talk about specific topics without straying too far from them.

Points to bear in mind

Level 3 corresponds more or less to semi-structured interviews. An interview guide is essential; you must define the main themes and various sub-themes to navigate between.


Level 4: the open-ended interview

The fourth level is the “open-ended interview,” which uses precise but openly formulated questions to leave the subject free to answer.

When to use it?

This type of interview is still quite rare in market research. It’s designed to be rather short (regarding administration time), as the interviewee’s voice is highly directed. This type of interview could be used to assess an interaction in a retail context, for example, at the checkout.

Points to bear in mind

The main point of attention concerns the definition of open-ended questions and their use. Since the questionnaire will contain the same questions for all respondents, how to analyze the results also arises.


Level 5: the closed-ended question interview

Finally, the fifth level is the “closed-ended interview,” in which the subject answers predefined questions.

When to use it?

This type of interview is similar to a quantitative survey. Closed-ended questions leave no latitude other than that given by the measurement scale. Therefore, interviews based on closed-ended questions are not a qualitative methodological approach. You can use it in telephone surveys, particularly satisfaction surveys. Short interviews of this type can also be used in retail environments to measure something specific: an NPS at the checkout or a customer experience in a particular department.

Points to bear in mind

For this type of interview to be effective and provide reliable answers, it must be administered as close as possible to what is being measured. It is, therefore, an “on-the-spot” measurement. As in the previous level (open-ended interview), care must be taken to ensure the closed-ended questions are correctly defined. They must provide a reliable measure. Choosing the right scale is particularly important.



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