PO217 Lecture Notes - Lecture 9: Natural Experiment, External Validity, Internal Validity
Document Summary
Advantages of open-ended questions: open-ended questions avoid the disadvantages of close-ended questions, open-ended questions provide rich contextual material, often of an unexpected nature. Disadvantages of open-ended questions: easy to ask difficult to answer and more difficult to analyze. Increase the possibility of interviewer/researcher bias: take up more interviewing time and impose a heavier burden on the interviewer, require more processing, respondents may give answers that are irrelevant. Ordering the questions: question sequence is just important as question wording. The order in which questions are asked can affect the responses given: make sure open-ended and close-ended versions of the same question are widely separated and that the open-ended version is asked first. Interviewer effect: longitudinal studies, metadata, microdata, non-response bias, omnibus surveys, open (open-ended) questions, secondary data. Topic 11 overview: why is research design important, review nature of causal inferences, the classic experimental design. Internal vs external validity: types of experiments.
