Regardless of the topic of your dissertation or thesis, it is highly likely that at some point you will need to collect data. Below are some common data collection methods. Remember, you will want to collect data in a way that fits your research design and questions.
Self-report is a type of research design in which participants give their responses to a given set of questions. The most common types of self-report are interviews or questionnaires. One major limitation of self-report versus other data collection methods is that accuracy of responses cannot be determined, and there are many circumstances in which participants are likely to lie.
Observation is a method of collecting data in which members of research teams observe and record behaviors. Data collected during observation are explicit and quantifiable. However, observation has many limitations. First, researchers who use observation can only observe behaviors; therefore, observation cannot be used to collect data about attitudes, beliefs, thoughts, covert behaviors, etc. Another limitation of observation is that it is a known fact that being observed changes behavior. Observation can be either formal (e.g., structured in a laboratory setting) or casual (e.g., in the natural environment), and the observer may either be a participant (e.g., member of the group being observed) or a nonparticipant (e.g., not a member of the group being observed).
Physiological measures can be used to collect data related to the body, such as heart rate, fMRI, EEG, CAT, breathing rate, etc. These types of data are useful because they are quantifiable and accurate. However, these types of data are sometimes used as secondary measures of latent constructs, which may not always be accurate. For example, someone with a high heart rate may be perceived as being anxious, but it is possible that that person just walked up a flight of stairs.
Interviews are one of the data collection methods for qualitative research. Interviews consist of meeting with participants one on one and asking them open-ended questions. Interviews can be structured or semi-structured. In a structured interview, the researcher has a predetermined set of questions to ask and does not deviate from those questions. In a semi-structured interview, the researcher will have prepared questions but has the freedom to ask additional follow up questions as he or she sees fit.
Focus groups are another example of data collection methods of a qualitative study. Using focus groups to collect data is similar to using interviews because focus groups allow participants to freely answer questions; however, as implied by the name, focus groups consist of multiple people all being asked questions at the same time.