Beyond Saturation: Using Data Quality Indicators to Determine the Number of Focus Groups to Conduct

 The following is a modified excerpt from Applied Qualitative Research Design: A Total Quality Framework Approach (Roller & Lavrakas, 2015, pp. 130-131).

Qualitative researchers are routinely faced with the decision of how many in-depth interviews (IDIs) orSaturation focus group discussions to conduct. This decision often revolves around time-cost-benefit trade-off considerations fueled by the tension between neither wanting to conduct too many nor too few IDIs or focus groups.

When it comes to the focus group method, the decision of how many group discussions to conduct is based on any number of factors and will vary depending on the situation for each study.  However, a few of the critical factors that the prudent researcher will think about when considering the number of discussions at the outset for any focus group study are the:

  • Geographic range of the target population, e.g., whether the target population for in-person groups is located in one city or spread across the U.S.
  • Depth of the discussions, i.e., the number of topics/issues and questions expected to be covered to satisfy research objectives. For example, fewer group discussions may be necessary if the primary research objective is to learn mothers’ preferences for shelf-stable baby food, while a greater number of groups may be needed if the objective is to understand mothers’ preferences across all types of baby food and, specifically, to investigate the priority they place on nutritional and organic foods.
  • Homogeneity or heterogeneity of the group participants. Using the example above, more groups will be required if the mothers of interest range in age from 25-40 years as well as in income level and if there is reason to believe that attitudes and behavior vary across these demographic characteristics.
  • Variation in results that is expected to occur across the different focus groups that will be conducted. If there is little variation expected from one group to another (e.g., if group participants are highly homogeneous, or the attitudes among participants in New York are not expected to be different than those in Dallas), then only a few focus groups may suffice.  If there is a great deal of variation expected, then many focus groups will be required to fully measure the range of experiences, attitudes, and knowledge the participants will have to impart in the discussions.
  • Project schedule and amount of available time to complete the study.
  • Research budget that is available to fund the study.

It is this assortment of factors that cause qualitative researchers to generally disagree on the optimal number of Read Full Text

Designing a Quality In-depth Interview Study: How Many Interviews Are Enough?

Here is a topic that is worthy of more discussion in the research community: What is the optimal number of in-depth interviews to complete in an IDI study?  how-many-interviewsThe appropriate number of interviews to conduct for a face-to-face IDI study needs to be considered at two key moments of time in the research process – the initial research design phase and the phase of field execution.  At the initial design stage, the number of IDIs is dictated by four considerations: 1) the breadth, depth, and nature of the research topic or issue; 2) the hetero- or homogeneity of the population of interest; 3) the level of analysis and interpretation required to meet research objectives; and 4) practical parameters such as the availability and access to interviewees, travel and other logistics associated with conducting face-to-face interviews, as well as the budget or financial resources.   These four factors present the researcher with the difficult task of balancing the specific realities of the research components while estimating the optimal number of interviews to conduct.  Although the number of required interviews tends to move in direct step with the level of diversity and Read Full Text