Qualitatively Speaking: The focus group vs. in-depth interview debate

Editor’s note: Carey V. Azzara is founder and principal of AtHeath, a Newton, Mass, research firm.

If debate is healthy, you might describe the debate over qualitative methods as positively athletic. There are plenty of opinions regarding which qualitative approach provides the best results. You, no doubt, have your own opinion.

To explore the reasons professionals feel strongly about the merits of focus groups (FGs) versus in-depth interviews (IDIs), we asked 20 of them when and why they choose to use FGs versus IDIs. The themes that emerged from our asynchronous debate process are illuminating.

In general, there were three, somewhat predictable, positions: one-on-one interviews are superior to focus groups; focus groups are superior to one-on-one interviews; align the research approach with the research objectives.

Each person who took one of the first two positions gave well-thought-out reasons for his or her choice. It typically related to the specific research problem they faced. Another reason for a preference was skill. Practicing what you know how to do best makes sense. Many professionals are better at one approach than another; this factor obviously plays a role in the choices practitioners make.

Aligning the approach with the objectives was an overarching theme even among professionals who strongly favor one technique over the other. Thus, our next questions are, what are the “when and why” answers experts gave? And, can we create a concise best-practice statement from the collective wisdom of 20 practitioners?

Arguments for in-depth interviews

IDIs provide the best opportunity to explore decisions and compare differences and similarities among reference group members. When the research objective is to understand individual decision processes or individual responses to marketing stimuli (e.g., Web sites) IDIs are typically the choice. IDIs allow detailed exploration of a single respondent’s reactions without contamination. They are particularly valuable when researchers want individual reactions placed in the context of the individual’s experiences.

A preference for IDIs is likely when group interactions are unimportant or detrimental. A few scenarios are:

• when it is easier to reach target respondents with IDIs;
• when there is a better cost-benefit for IDIs;
• when it is preferable to collect responses without the group influence factor;
• when probing and/or laddering techniques are part of the data collection process;
• when project objectives require a direct correspondence of specific findings to specific respondent segments; and/or
• when a device or process is being tested for usability.

Additionally, if the topic is highly sensitive (e.g., serious illnesses) use of IDIs is indicated. Subjects which are highly personal (e.g., bankruptcy) or very detailed (e.g., divorce decrees) are best probed deeply with IDIs.

Sensitive subjects are also a factor in business research. Topics with competitive consequences are sensitive areas (for example, companies consider information-technology practices proprietary, especially security technology). In addition, businesses are wary of participating in FGs with competitors (such as when participants are from the same vertical industry, etc.).

A preference for IDIs was evident when:

• working with small populations, especially if geographically-dispersed;
• avoiding operational pitfalls is a concern (e.g., the threat of 60 percent of a group cancelling or possibly inviting the wrong people; it’s easier to recover from one bad-fit IDI than a FG with eight people); and
• you need deep layers of information from probing (e.g., interviewing “experts”).

In the final analysis IDIs are a practical approach and typically easier to manage. However, it’s important to distinguish between the ease-of-use factor versus the better-approach factor!

Arguments for focus groups

Several versions of the following comment were typical: “My rule of thumb is to assume focus groups and switch to IDIs only if necessary.” A basic question is, “Will the group dynamics add to the findings?”

There are triggers to suggest when to do groups versus using other qualitative approaches. FGs are particularly compelling:

• when consensus or debate is required to explore disparate views;
• to generate opportunities for point-counterpoint discussion and resolution;
• as an excellent approach for broad, exploratory topics, and as a mechanism for helping people generate and share their ideas;
• when the interaction between the participants sparks a discussion that illuminates a topic, draws out latent issues;
• when you want people to work in teams;
• when the rich quality of respondent interactions is needed or you are exploring common trends; and/or
• when you are early in the exploration of a concept or topic, as group dynamics are powerful in the discovery process.

Focus groups have an advantage when trying to engage clients (decision-makers) in the research process. When research sponsors take time to view focus groups it expedites their buy-in, moving the study to final recommendations faster. You are less likely to “lose” your client in the course of two or four hours compared to the time associated with IDIs. For some practitioners focus groups were preferred when speed is important, but apply caution here: advocates of IDIs use this argument too. FG practitioners believe IDIs take longer to execute than FGs and are harder and more time-consuming to analyze.

Focus groups of no more than eight respondents was a recommendation echoed by several practitioners. Triads and mini-groups were suggested as alternatives for generating ideas while allowing in-depth questioning. Mini-groups are well-suited to obtaining reactions to product stimuli and generating refinements. Contrary to most opinions, sensitive issues are not only okay in groups, but may be explored as well as or better than in IDIs, because respondents engage when discussing their condition or issue with others in the same boat.

Finally, the statement, “I favor the group situation; people are forthcoming among peers when attention is focused on many rather than one,” depicts a popular position.

Two themes

Two themes emerged that we can use to construct a best-practice statement. The first is characterized by the mantra, “Objectives drive design.” Evaluate critically the research objectives and apply the approach most likely to provide insights. A good practitioner chooses the best method for the work and the selection process requires understanding the merits of all available approaches.

A key question is whether the objectives are individual in nature (e.g., decisions, preferences, usability) or group-oriented and benefit from participants’ discussion or perhaps arguments (e.g., concept exploration).

The second theme is summarized by the simple comment, “Why not use both?” Designing qualitative research using IDIs and FGs provides the best of both worlds - and it’s not a cop-out! IDIs provide depth of questioning and personal information while FGs help us understand the social context of issues. The methods are complementary.

For business decision makers, combining the benefits of IDIs and FGs is a great solution if the budget supports it. In fact, perhaps the only real argument against this approach is concern about exceeding a project’s budget.