Editor’s note: Naomi Henderson is CEO of RIVA Market Research, Inc., Bethesda, Md.
Qualitative research moderators often prefer to work with a specific number of respondents, for reasons of interviewing comfort and for how group size affects the research objectives. This article outlines some issues related to focus group size and desired research outcomes, since the size of the group (i.e., number of respondents) affects the skilled moderator’s ability to get below top-of-mind comments.
Group size and research objectives are closely aligned. The "right" group size is often a function of a client’s need for specific results to support long-range decision making. For example, a client may request a group size of four to six respondents when a few, very important issues need to be discussed in detail. A group size of 12 may be right when the study is a one-hour "ad lab" designed to get a thumbs-up/thumbs-down reaction to the final three versions of a TV spot.
Sometimes the right group size is a function of room size. Recently, a focus group held in a mall facility required the use of a room with a round table that would only accommodate six respondents and a moderator without extreme discomfort. When a pregnant respondent had to leave to use the rest room, everyone had to stand to let her pass by to get out the door! Clearly, room size dictated group size.
In focus group planning, research design is often a blend of moderator experience (knowing how to reach the study objectives) and an attempt to honor client requests. Over the years, I’ve heard these quotes from my qualitative research colleagues as they identify personal rules about group size:
"I insist on no more than six, because that size lets me get a lot of answers from everyone."
"It’s OK with me to take 10 or 12 in a group because I know then that at least eight or nine of them will talk enough to get all the data - and I hate to turn people away who have been invited to a focus group."
"For me, seven is the perfect number. I like it when it is an uneven number of people because then I as the moderator become the eighth person."
"I know that conducting triads is the best research tool sometimes. However I just HATE them because I have to work much harder as a moderator to keep the creative juices flowing!"
For each of the above moderator types, there is a rationale for a group size that works and it is from that base that moderators lobby for a specific group size within the confines of good qualitative research design. Sometimes, clients have "belief categories" about group size:
a.) "More is better"
b.) "Corporate policy"
c.) "Feels right"
When more is not better
When I can negotiate research design elements with clients, I first have to break the "more is better" rule and to that end, I have devised a formula to share with clients so they can see that more bodies in the room actually hampers the collection of data rather than promotes it:
Formula for Calculating Research Value By Group Size
If 12 people are present = Allows 1.66 min. per issue per person
If 10 people = 2 min. per issue per person
If eight people = 2.5 min. per issue per person
If six people = 3.3 min. per issue per person
In the formula, it’s clear that the more people in the room, the less time there is available for actually getting respondent opinions! The trick is to find the mix of people and talking time that best helps meet study objectives. When the group size shrinks to below six respondents, a different group dynamic occurs. Smaller groups sometimes get shy when given a lot of time to present an opinion. Different moderator skills are needed to maximize the time. The session is usually shorter than two hours since topics can be covered in-depth more quickly.
Corporate policy on group size dictated by non-moderators
Some clients insist that a specific group size is "corporate policy" and the demand seems to include a whisper of "we have always done it that way." RIVA’s concern is that the policy is often stated or upheld by individuals who have never led a focus group. I’m always unclear about the rationale that would have a client set a policy about group size without the personal experience of how group size affects group dynamics and the ability to collect full and rich data from participants.
When feeling right feels wrong
Group size is sometimes determined by a client who indicates that "six feels about right" for this project. Feelings are the domain of focus group conversations between the moderator and respondents and not an appropriate mechanism for determining research parameters. The moderator’s experience in knowing which group size best matches the research tasks is a better gauge than client observers’ expectations of which group size will produce which desired outcome.
The magic of eight
In the RIVA method of conducting focus group research, we believe in the "magic of eight" for traditional focus groups. The group can act as an octet, two pairs of four or a quartet of pairs. Assuming that all participants speak equally on each of the issues - eight people will each speak 2.5 minutes per issue or about 12 minutes over the course of a two-hour group session. When compared to TV news sound bites, each lasting about 30 seconds, 12 minutes is a long time to allow a respondent to have the floor!
As it turns out, individuals in focus groups don’t speak equally! On one topic, two to three participants speak more than others and on another, a different set of four to five respondents will lead the discussion.
Since there is insufficient time for each person to answer every question, the RIVA method aims for the "two-thirds" rule. If two-thirds of the group members have answered the question under discussion, the moderator asks if there are any different points of view. If not, then the group moves on to the new topic. Under that rule, we don’t expect every person to answer every question on every issue - just those who have a point to make or a point to contradict or echo what has already been said.
We have found that a group of eight allows for the following to naturally occur:
- Respondents don’t have to wait too long for a turn to speak.
- There is no chance for a respondent to hide out in a group of eight and everyone can be easily seen around a conference table.
- There is enough variation in eight respondents for participants to find someone else who thinks the way they do.
- There is enough conversation to promote an opportunity for diverse opinions and natural give-and-take.
Having eight respondents in the room also seems to allow for a level of comfort among respondents. The table seems full without being crowded and there is sufficient room to allow for the Western cultural need for about three feet of space between people in groups. Respondents can see the faces of most of the other participants easily and can make eye contact with a peer (one who shares the same opinions). When the group is divided for a task (e.g., two teams sorting pictures to create brand image), it is easy to form the quartets without anyone having to change seats - simply working across the table in a group of four at either end of the table. If the group is divided into sharing pairs, the even number of participants makes that an easy task and instructions can be given and followed quickly. If the session is being videotaped, it is easy to structure the seating so that it looks natural and allows every face to be captured on the behind-the-mirror camera.
Although a traditional focus group takes place in a time slot of two hours, there is actually only about 100 minutes of true research time since the remaining 20 minutes is generally used up in getting respondents seated and introduced to the topic and then excused and escorted from the room. That 100 minutes of research time needs to be used wisely. Having a manageable group size that promotes the inclusion of respondents on every topic and allowing time to go beyond top of mind responses means that group size has to be carefully planned.
Win-win-win
Blending group size with moderator comfort and client research needs is tricky. For traditional focus group projects primarily aimed at testing respondent perceptions, opinions, beliefs and attitudes, RIVA moderators have found that the "magic of eight" promotes a win-win-win situation for moderator, client and respondent. Facilities are asked to recruit 10-11 to guarantee a show rate of eight and they win as well by having a project that is manageable - not only in the recruiting process but in the waiting room as well.