Also very good for product design questions. Focus Group A gathering of about ten people who talk about a product or service with a skilled moderator. The moderator focuses the discussion to learn how people feel about the topic of discussion. Useful as an exploratory step to provide input into further testing. The sample size is too small to generalize in a meaningful way.
Value is highly dependent on the moderator.
Personal interviewing, canvassing Phone interview Mail questionnaire When properly constructed, more accurate than observation and focus groups. Experimental Subject matched groups of people to different treatments while controlling extraneous variables and checking whether the observed responses are statistically significant. The most scientifically valid method. Very difficult for customers to extrapolate more than a tiny distance from their present way of doing things. Very difficult for customers to extrapolate more than a tiny distance from their present way of doing things.