The following article appeared in
Total Communication Measurement, April 2000
Melcrum Publishing Ltd., London

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How many focus groups do you need?
Choosing the right number and types of groups is part art and part science

By Angela D. Sinickas, ABC

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One of the most frequent questions I hear about focus groups is, "How many should we conduct?" Unfortunately, there is no magic number or percentage. On the bright side, I do have some suggestions on how to determine the right number for your own research project. Your goal should be to conduct the fewest number of focus groups that will provide the widest range of input. That will use time and money the most wisely.

Will you also have a survey?

If you conduct focus groups before a survey, you don't need to conduct them for each demographic subgroup. The survey will capture that data for you. Just be sure to pick representative groups that will provide insights into a wide variation of perspectives to make sure all the right issues are addressed on the survey.

For focus groups probing issues after a survey, you can use the survey results to identify subgroups ( eg. those that were about average on their results, much more negative and much more positive) to probe the differences in those groups.

However, if the focus group research will stand alone without a companion survey, you may need to conduct more focus groups because you will have no other way of identifying variations by subgroup.

How might results vary by types of people?

Depending on the topic you're probing, different types of people are likely to have different experiences. Brainstorm with your colleagues what those relevant differences might be to make sure you conduct at least one focus group where that characteristic is represented.

For example, for employee groups, results might vary by:

• job type (either nature of job or union status)
• job level (hourly, salaried or supervisory)
• full-time versus part-time hours
• shift worked
• length of service

Characteristics that might be important for consumer focus groups might include:

• Whether participants currently use products/services like yours;
• Whether they are your customers or your competitors'
• Family income
• Age
• Sex

How results vary by location?

Many issues are experienced differently because of where the participants are just as much as who they are.

Potential differences for employee focus groups:

• business unit;
• size of location;
• distance from headquarters;
• profitability/productivity levels;
• how long the location has been in operation;
• how long the same executive has been in charge of the location;
• previous survey results.

Potential differences due to location for consumer focus groups:

• Geographic trends in purchasing patterns
• Exposure to different advertising levels or approaches
• Availability of products or services
• Cultural differences

Then build a matrix

Once you've identified all the relevant potential variations, create a grid similar to the Figure One below. Then begin listing potential sites at which to conduct the focus groups. For each characteristic, start with one or two most representative locations for that characteristic. For example, with employee focus groups, write in your largest location and your smallest, your most profitable and most dismally unproductive. Do the same with each characteristic. Also try to think of locations where a variety of criteria might be met in one visit ( for example, a city where you have local operations of three business units). 

Once you've listed a good range of potential locations, complete the entire grid for each location. Then try to find the fewest locations to visit that will provide the widest range of differences among the categories. This takes some trial and error. You may need to replace some locations with others. For example, instead of using your largest site, you might choose your second largest because it has employees working all three shifts.

As you select your locations, remember that you probably don't need to conduct focus groups in every possible combination of variations. For example, you may not need to conduct focus groups with every shift in every size of location. As long as you have at least one focus group somewhere for each shift, that will suffice. Just make sure to probe for shift issues in those focus groups.

Figure 1:Sample focus group selection worksheet

Angela Sinickas, ABC, is president of Sinickas Communications, Inc., a communication consultancy specializing in helping corporations achieve business results through targeted diagnostics and practical solutions. You can visit her new website, CommToolbox.com, to see the automated planning, measurement, and benchmarking tools she has developed based on her manual, How to Measure Your Communication Programs.