-Self-report accesses what people think and feel, not possible through observation
-Answers may lack validity because social desirability bias and/or people don’t know what they actually think. Sample may be unrepresentative.
-Questionnaires: collect data from large number of people, people may be more willing to reveal confidential information than in an interview
-Questionnaires: can only be filled in by people who can write and have the time, a biased sample
-Structured interview and questionnaire: can be repeated exactly, good for making comparisons between people and good for analysis
-Structured and unstructured interviews may be affected by interviewer bias
-Unstructured interview: more detailed information, more issues with interviewer skills and bias, more expensive because of training needed