There are three types of major marketing research methods in which I am familiar with: questionnaire, case study, interview, and recently observational.
             Questionnaires are an inexpensive way to gather data from a potentially large number of respondents. Often they are the only feasible way to reach a number of reviewers large enough to allow statistically analysis of the results. A well-designed questionnaire that is used effectively can gather information on both the overall performance of the test system as well as information on specific components of the system. If the questionnaire includes demographic questions on the participants, they can be used to correlate performance and satisfaction with the test system among different groups of users.
             Case studies are particularly useful in depicting a holistic portrayal of a client's experiences and results regarding a program. For example, to evaluate the effectiveness of a program's processes, including its strengths and weaknesses, evaluators might develop cases studies on the program's successes and failures. Case studies are used to organize a wide range of information about a case and then analyze the contents by seeking patterns and themes in the data, and by further analysis through cross comparison with other cases. A case can be individuals, programs, or any unit, depending on what the program evaluators want to examine through in-depth analysis and comparison.
             Interviews are particularly useful for getting the story behind a participant's experiences. The interviewer can pursue in-depth information around a topic. Interviews may be useful as follow-up to certain respondents to questionnaires, e.g., to further investigate their responses. Usually open-ended questions are asked during interviews.
             The drawbacks include: focus group interview may be dominated by stronger personalities, participants may not be willing or able to admit in public their behavior patterns an...