Because focus group interviews are conducted in groups, a single opinion expressed by one member can often sway other participants. J. Scott Armstrong, a researcher from the University of Pennsylvania calls this "bandwagoning," where members of a focus group seize on to an opinion and expand on it, which can sway the dynamics and opinion, and therefore the results, of the focus group research. Armstrong explains that in some types of sociological research, the "bandwagoning" effect may in fact be the goal: if the researchers are aiming to reflect or recreate existing biases in the real world, a focus group may be an efficient and accurate method of doing so. For scientific research that requires unbiased research, though, Armstrong advises against using focus groups.
Focus groups are primarily used in market research to test a product on a target demographic and gauge reactions. Focus groups are often invited to test screenings of television pilots and movies to offer feedback, which can lead to edits, rewrites or even scrapping an entire film project, based on the focus group's reactions. Critics of focus groups, like the University of Pennsylvania's J. Scott Armstrong, believe focus groups are detrimental to decision making. In 2004, Warner Brothers announced they would stop using focus groups to test new television shows.
Focus groups are often used to discover what changes or new techniques should be implemented in an existing system. A 2001 paper presented by Larry Katz and Amanda Williams at the University of Calgary suggests using focus groups to implement new educational techniques and curriculum changes by asking the groups about their knowledge of curriculum issues and what topics they would like to see covered in schools. Katz and Williams specifically mention cases in which focus groups were used in the 1990s to address student, parent and teachers' desire to have curricula introduced to cover AIDS, nutrition, sexual education and new technology into the classroom.
Any research requiring qualitative, rather than quantitative, data can make use of focus groups. Many sociologists use focus groups, either as self-contained research or in conjunction with surveys and other forms or simply as a preliminary source of qualitative information before implementing more scientific research methods. Focus groups can expand on simple survey answers and give researchers a more complete view of their survey results, such as highlighting reasons for different answers, or perhaps different conditions in which participants may agree on an answer.