(1) There are two main forms of survey, and each has its own advantages. (2) One type of survey
is the interview. (3) An interview can obtain a high response rate because people find it more
difficult to turn down a personal request for an interview than to throw away a written
questionnaire. (4) In addition, a skillful interviewer can go beyond written questions and probe
for a subject's underlying feelings and reasons. (5) Questionnaires, the second main form of
survey, also have two advantages. (6) They are cheaper than interviews, especially when large
samples are used. (7) Moreover, since the questions are written, the researcher knows that there is
a guarantee of consistency, whereas five interviewers can ask the same question in five different
ways.
C9. In general, the major details of this passage are