Sampling Procedures for Focus Groups
When researchers approach focus group interviewing, they carry with them many of the traditions, wisdom, and procedures that were intended for experimental and quantitative studies. Some of these procedures readily transfer; others do not.

Consider random sampling. Most researchers "cut their teeth" on randomization. Because these procedures served them well in some arenas, they may assume that the same procedures are also appropriate for qualitative studies in general and focus group interviews in particular. Randomization essentially removes the bias in selection-that is, all participants possess an equal chance to be involved in the study. Random selection is particularly appropriate when inferences are made to a larger population because of the assumption that opinions, attitudes, or whatever being studied will be normally distributed within that population. Therefore, a random sample of sufficient size will be an adequate substitute for surveying the entire population.
Keep in mind that the intent of focus groups is not to infer but to understand, not to generalize but to determine the range, and not to make statements about the population but to provide insights about how people in the groups perceive a situation. Although a degree of randomization may be used, it is not the primary factor in selection.
When randomization is used in focus groups, it is often for the purpose of eliminating selection bias inherent in some forms of personal recruitment. Typically, lists provide more names than needed, and either a systematic or random sampling procedure should be used in picking the actual names to recruit. In a systematic sample, each with number is picked. For example, if ten names are needed from a list of 200, every twentieth person on the list is selected. A random sample consists of drawing names or ID numbers out of the hat or using a random number table to select from the list of 200 people.
TIP
Focus Groups Within Organizations
At times, the focus group interview is used with groups that are already established, such as employee work groups, boards of directors, or colleagues. These existing groups may have formal or informal ways of relating to each other that can influence their responses. Superior-subordinate relationships among participants can inhibit discussion. The focus group technique works well when all participants are on an equal basis, but if supervisors, bosses, or even a friend of the boss are in the group, the results might be affected.
Employees might be reluctant to express negative observations in front of coworkers, especially if supervisors are present. Focus groups should be conducted without the presence of supervisors. The key is to help employees comfortable. They often want to know who asked for the information, why they asked for it, what decisions will be made with the infor mation, that their comments are confidential, that their names will not be attached to any reports, and who will have access to the audiotapes.
Although the purpose dictates the nature of the selection, practical concerns and credibility temper the process. With all sampling strategies, you must be concerned about the degree to which that strategy could lead to distortions in the data. Anticipate questions about the means of selection and be able to provide the rationale for those decisions.