Although qualitative research produces useful information, it has some potential
disadvantages, including small sample sizes and the need for well-trained interviewers
or observers. The sample size in a qualitative study may be as few as 10 (individual indepth interviews), and is rarely more than 60 (the number of participants in 5 to 6 focus
groups).
Occasionally, companies will undertake large-scale qualitative studies involving
thousands of in-depth interviews and hundreds of focus groups, as Forrester Research
did to support the development of their e-commerce consulting business,7 but this is the
exception, not the rule. While researchers often handpick respondents to represent their
target population, the resulting samples are not representative in the statistical sense.
Qualitative researchers emphasize their samples are made up of ‘‘relevant’’ rather than
representative consumers. The lack of representativeness of the defined target population may limit the use of qualitative information in selecting and implementing final
action strategies.