In this section we highlight some of the standard survey procedures for obtaining high cooperation rates once contact with the subject has been established. These can be divided into issues of interviewer training, the questionnaire, and the treatment of refusals.
Interviewer Materials and Training
Interviewer experience has been found to be related to obtaining high respondent cooperation (Groves and Fultz, 1985; Dillman et al., 1976). The theory is that experience makes interviewers familiar with many questions reluctant respondents may have about cooperating (Collins et al., 1988), and allows them to respond in a quick and confident manner. Showing any type of hesitation or lack of confidence is correlated with high refusal rates.
This finding suggests that intense training of interviewers on how to handle reluctant respondents may provide them with increased confidence, as well as the necessary skills, to handle difficult situations. Groves and Couper (1998) present results from an experiment on an establishment survey that shows significant improvement in cooperation rates once interviewers are provided with detailed training on how to handle reluctant respondents. This training consisted of drilling interviewers, through a series of role plays, on providing quick responses to respondent concerns about participating in the study. Because this study was done in an establishment survey, the applicability to a survey of low-income respondents is not clear. Respondents to establishment surveys are more willing to converse with the interviewer, which allows for more time to present arguments on why the respondent should participate in the study.
Nevertheless, this suggests that interviewers must have the skills to answer the subjects questions, to overcome objections, and to establish the necessary rapport to conduct the interview. Training in these areas is crucial if refusals are to be avoided. Answers to Frequently Asked Questions (FAQs) must be prepared and practiced so that the answers sound like the interviewers own words rather than a script that is being read. Interviewers also must be trained to know when to accept a refusal, leaving the door open for future conversion by a different interviewer who might have more success. This type of training is more difficult than training that is centered on the content of questions, but it is also vital if refusals are to be avoided.
Several areas related to the design of the questionnaire could impact response rates. These include: (1) the length of the questionnaire, (2) the introduction used, and (3) the type and placement of the questions. Each of these has been hypothesized to affect the ability of the interviewer to obtain a high response rate. Interestingly, for each of these characteristics, there is some belief that the effects are primarily on the interviewers perception of the task, rather than concerns the respondent may have with the procedure. If interviewers perceive the task to be particularly difficult to complete, their confidence levels may go down and their performance might be affected.
Pretests of the questionnaire should be conducted as part of any research design. Pretests, and accompanying debriefings of the interviewers often uncover problems that are easily corrected prior to interviewing the sample subjects. More elaborate pretesting methods also should be considered. These include, for example, cognitive interviews, as well as review of the questionnaire by a survey research professional who has experience in conducting structured interviews.
Questionnaire length. Although it is commonly believed that the length of the questionnaire is related to response rates, very little empirical evidence shows that this, in fact, is true. Much of the evidence that does show a relationship between length and response rates concerns mail surveys, where respondents get visual cues on how long the interview may be (Bogen, 1996). The length of a telephone interview may not be mentioned unless the respondent asks, so the respondent may not know how long it will take. This fact further confuses the relationship between interview length and response rates.
Two exceptions to this are studies by Collins et al. (1988) and Sobal (1982). Both found a relationship between how long the interviewer told the respondent the interview would take and the response rate. Collins et al. (1988) found a modest effect of approximately 2 percent, while Sobal (1982) found a much larger reduction of 16 percent when comparing a 5-minute interview to a 20-minute interview. These studies, however, are difficult to generalize to other studies because they do not compare the effects of different descriptions of the length of the interview to one that does not state the length at all. This makes it unclear what the overall effect of interview length might be in the context of another survey, which does not state the length of the interview (unless asked).
This research does suggest, however, that significantly shortening the interview to 5 minutes may increase response rates to some degree. If the interview were shortened to this length, then it might be advantageous to state the length of the interview in the introduction to the survey. One would assume that cutting the interview to just 5 minutes is not an efficient way to increase the response rate. The loss of information needed for analyses will be much larger than anticipated gains in the response rate. For this reason, it might be useful to consider shortening the interview only for a special study of refusers. If this strategy significantly increases the number of persons who are converted after an initial refusal, more information might be obtained on how respondents differ from nonrespondents.
Survey introduction. A natural place to start redesigning the questionnaire to improve response rates is the introduction. Many respondents refuse at this point in the interview. This is especially the case for an RDD survey, where interviewers do not have the name of the respondent and the respondent does not recognize the voice on the other end of the call. For this reason, it is important to mention anything that is seen as an advantage to keeping the respondent on the line. Advantages generally are believed to be: (1) the sponsor of the study, (2) the organization conducting the interviews, (3) the topic of the survey, and (4) why the study is important.
Research in an RDD survey context has not found any general design parameters for the introduction that are particularly effective in increasing response rates. Dillman et al. (1976), for example, find no effects of offering respondents results from the survey or statements about the social utility of the survey. Similarly, Groves et al. (1979) find variations in the introduction do not change response rates. Exceptions to this are a few selected findings that: (1) government sponsorship seems to increase response rates (Goyder, 1987), (2) university sponsorship may be better than private sponsorship, and (3) making a nonsolicitation statement (e.g., I am not asking for money) can help if the survey is not sponsored by the government (Everett and Everett, 1989).
The most widely agreed-on rule about introductions is that they need to be as short as possible. Evidence that shorter is better is found in Dillman et al. (1976), as well as our own experience. Because the interviewer may not have the full attention of the respondent at the initial outset of the call, it is better to simply state the best points of the survey and get the respondent to react to the first question. Interviewers also generally prefer short introductions, because they provide a greater opportunity to involve the respondent in the conversation (less opportunity to hang up). By increasing interviewer confidence, the response rate should be affected positively. It is important to balance the informational requirements with the need to be brief and simple. Long explanations, going into great detail about the survey, may turn respondents off more than motivate them to participate. The best approach is to provide the respondent with a broad set of statements to capture their attention at this point in the interview. Once rapport and trust have built up a bit, more details about the study can be presented.
Type/placement of questions. Sensitive questions have higher rates of nonresponse and should be placed later in the questionnaire but still positioned logically so that the flow from one topic to the next is smooth. Sensitive information includes topics such as income, detailed household composition (e.g., naming everyone in the household), participation in social programs, and child care. Careful placement allows these questions to be asked after rapport has been established. This is especially true with initial contacts into the household. Asking sensitive questions within the first few minutes of the initial contact may turn respondents off unnecessarily.
If a respondent refuses to participate, it is important for the interviewer to indicate the level of hostility, if any. It may not be desirable (nor cost effective) to try to convert subjects who are extremely hostile (e.g., one in which the respondent is abusive). Other subjects might be recontacted in an attempt to have them reconsider their decision. This recontact should take place several days (7 to 21) after the initial contact to allow the respondent time to reconsider.
Prior to refusal conversion, a letter should be sent to try to convince the respondent to participate. This letter has been shown to be particularly effective if: (1) an incentive is enclosed, and (2) express delivery is used for mailing (Cantor et al., 1999). Comparisons between the use of express delivery to a first class refusal conversion letter show a difference of 10 percentage points in conversion rates on an RDD study and a difference of 15 to 20 percentage points if an incentive is enclosed. These results are not likely to be as dramatic for a survey of welfare leavers. However, this strategy has been applied in this context and is believed to be effective.
Based on work related to personal interviews (Couper et al., 1992), it is possible to create specialized letters for refusal conversion based on what the respondent said at the time of the refusal. A procedure adopted for the National Survey of Americas Families (NSAF) was to have the interviewer provide a recommendation on the type of letter that would be sent to the respondent after the refusal occurred. Because most refusals fall into two or three categories (e.g., no time, not interested), special letters could be developed that emphasized particular arguments why the respondent should cooperate (e.g., no time emphasize the length of the interview; can do the interview in several calls). The problem with this procedure is that for most refusals, the interviewer has little information on which to base a good decision on the reason for refusal. A large number of respondents hang up before providing detailed feedback to the interviewer. As a result, a large majority of the mailouts for the refusal conversion are done using the general letter, which does not emphasize anything in particular.
However, in a survey of welfare leavers, where the interviewer may have more information about the reason for refusal, tailoring the letters to the respondents concerns may be useful. This would depend on the amount of information the interviewer is able to collect on the reason for the nonresponse.
Refusal conversion calls are best handled by a select group of handpicked interviewers who are trained to carry out this type of work. They must be trained to analyze the reason for the refusal and be able to prepare answers for different situations.
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