Self Report In Research and Evaluation of Tools (VI)

Advantages of Interview and Questionnaire

Self Report In Research and Evaluation of Tools VI Advantages of Questionnaires,  Questionnaires Versus Interviews, Advantages of Interviews.

    Before developing questions, researchers need to decide whether to collect data through interviews or questionnaires. Each method has advantages and disadvantages.

Advantages of Questionnaires

    Self-administered questionnaires, which can be distributed in person, by mail, or over the Internet, offer some advantages. The strengths of questionnaires include the following:

    1:Cost. Questionnaires, relative to interviews, are in general much less costly and require less time and energy to administer. Distributing questionnaires to groups (eg, to students in a classroom) is clearly an inexpensive and expedient approach. And, with a fixed amount of funds or time, a larger and more geographically diverse sample can be obtained with mailed or web-based questionnaires than with interviews.

    2:Anonymity. Unlike interviews, questionnaires offer the possibility of complete anonymity. A guarantee of anonymity can be crucial in obtaining candid responses, particularly if the questions are personal or sensitive. Anonymous questionnaires often result in a higher proportion of socially unacceptable responses (ie, responses that place respondents in an unfavorable light) than interviews. 

    Interviewer bias. The absence of an interviewer ensures that there will be no interviewer bias. Interviewers ideally are neutral agents through whom questions and answers are passed. Studies have shown, however, that this ideal is difficult to achieve. Respondents and interviewers interact as humans, and this interaction can affect responses.

    Web-based surveys are especially economical, and can yield a data set directly amenable to analysis, without having to have staff entering data (the same is also true for CAPI and CATI interviews). Internet surveys also provide opportunities for interactively providing participants with customized feedback, and for prompts that can minimize missing responses.

Advantages of Interviews

    The strengths of interviews far outweigh those of questionnaires. It is true that interviews are costly, prevent respondent anonymity, and bear the risk of interviewer bias. However, interviews are considered superior to questionnaires for most research purposes because of the following advantages:

    1:Response rates. Response rates tend to be high in face-to-face interviews. People are more reluctant to refuse to talk to an interviewer who directly requests their cooperation than to discard or ignore a questionnaire. A well-designed and properly conducted interview study normally achieves response rates in the vicinity of 80% to 90%, whereas mailed and web-based questionnaires typically achieve response rates of 50% or lower. 

    Because nonresponse is not random, low response rates can introduce serious biases. (However, if questionnaires are personally distributed to people in a particular setting—eg, maternity patients about to be discharged from the hospital—reasonably good response rates can be achieved.)

    2:Audience. Many people simply cannot fill out a questionnaire. Examples include young children and blind, elderly, illiterate, or uneducated individuals. Interviews, on the other hand, are feasible with most people. For web-based questionnaires, a particularly important drawback is that not everyone has access to computers or uses them regularly even if they do.

    3:Clarity. Interviews offer some protection against ambiguous or confusing questions. Interviewers can determine whether questions have been misunderstood and can clarify matters. In questionnaires, misinterpreted questions can go undetected by researchers, and thus responses may lead to erroneous conclusions.

    4:Depth of questioning. The information obtained from questionnaires tends to be more superficial than interview data, largely because questionnaires typically contain mostly closed-ended items. Open-ended questions are avoided in questionnaires because most people dislike having to compose and write out a reply. 

    Much of the richness and complexity of respondents' experiences are lost if closed-ended items are used exclusively. Furthermore, interviewers can enhance the quality of self-report data through probing.

    5:Missing information. Respondents are less likely to give “don't know” responses or to leave a question unanswered in an interview than on questionnaires.

    6:Order of questions. In an interview, researchers have control over question ordering. Questionnaire respondents are at liberty to skip around from one section of the instrument to another. It is possible that a different ordering of questions from the one originally intended could bias responses.

    7:Sample control. Interviews allow greater control over the sample. Interviewers know whether the people being interviewed are the intended respondents. People who receive questionnaires, by contrast, can pass the instrument on to a friend, relative, and so forth, and this can change the sample composition. 

    Web-based surveys are especially vulnerable to the risk that people not targeted by researchers will respond, unless there are password protections.

    8:Supplementary data. Finally, face-to-face interviews can result in additional data through observation. Interviewers are in a position to observe or judge the respondents' level of understanding, degree of cooperativeness, social class, lifestyle, and so forth. Such information can be useful in interpreting responses. 

    Many advantages of face-to-face interviews also apply to telephone interviews. Long or detailed interviews or ones with sensitive questions usually are not well suited for telephone administration, but for relatively brief instruments, telephone interviews are more economical than personal interviews and tend to yield a higher response rate than mailed questionnaires.