When and Why to Choose Focus Groups vs. One-on-One Interviews

Written by Roger A. Straus

From a distance, focus groups and “one-on-one” interviews may seem to be virtually interchangeable. Both are intensively moderated, focused qualitative methodologies, but they have different strengths and weaknesses. The focus group is a group depth interview; it runs on group dynamics and the group, not the constituent individuals, is front-and-center. The individual depth interview (IDI) focuses on a single individual at a time. Typically, one can get more done in a shorter span of time using focus groups, but you can get far more depth with IDIs – you have up to an hour with each subject, while each group member gets only about 10 minutes to speak on average. You can do a typical two-group-per-day design in about four hours, versus an entire day for six to twelve IDIs. This condenses the time demand on busy observers and researchers.

Still, while a well-moderated group better simulates real-world dynamics (playing on peer-to-peer interaction), IDIs are easier to do with sensitive topics or rare respondent types, and require less skill to conduct effectively. They are also better adapted to telephone interviewing.

It makes sense, then, to consider the differences between groups and IDIs in terms of how each fits your needs. The following chart, used as a checklist, will help you with the decision. Ideally, you should choose the approach that maximizes relevant “pluses” related to your needs.


Objective/Consideration Focus Groups Individual Interviews

Discovery and exploration of new markets, concepts, etc.

++ +
  Simulate real-world response/maximize realism ++ +
  Get an overview ++ +
  Explore consensus or lack of ++ +
  Concentrate observer/research time and effort ++ +
  Understand commonalities within and differences between segments ++ +
  Avoid “please the interviewer” (rapport or transference) effects ++ +
  Understand differences within target segments + ++
  Gain detailed, in-depth individual understanding + ++
  Facilitate use of projective, other individual-based “depth” techniques + ++
  Explore very sensitive, embarrassing, controversial or “personal” topics + ++
  Avoid any potential for interpersonal bias + ++
  Study low-prevalence or hard-to-recruit respondent segments + ++

Study many different respondent segments or types

+ ++

This chart is intentionally designed to suggest that differences are relative – shades of gray, not black-and-white. There are variations that can allow you to take advantage of the fact that these differences are along a continuum with pure focus groups and pure IDIs at the polar ends. You can get the benefits of IDIs while still getting much of the benefit of focus groups, for example, by using mini-groups (4-5 respondents) or triads. Dyads, which are best managed like IDIs, allow for some of the dynamics one gets with focus groups. Furthermore, you can combine the two: e.g., schedule two or even three groups (e.g., one at breakfast, two in the evening) with IDIs during the rest of the day. You can interview less prevalent and /or hard to recruit respondent types individually, others in groups. In this way, you can reap the benefits of both methods. In the end, the best methodological decision is the one that supports your business goals.

Download a Free eBook with details on using Focus Groups at: www.atheath.com/booksandseminars

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