Interviewer Productivity

Literature

Interviewer productivity is discussed in the literature on survey methods. Don Dillman has noted the importance of interviewer productivity by indicating that the length of time taken to complete interviews needs to be taken into account in scheduling interviewers. Paul Lavrakas has proposed that interviewer productivity be measured by the speed with which samples are worked and also by the ratio of the number of completed interviews to the number of refusals and partially completed interviews. He suggests using these kinds of productivity measures to set interviewer pay rates and manage surveys. Interviewers who are more productive also have a greater influence on the amount of survey data collected than do less productive interviewers. This is because more productive interviewers end up completing more interviews than less productive interviewers. Robert Groves describes how estimates of the standard errors in a survey are directly related to the average number of interviews completed by each interviewer. In contrast, interviewers who are less productive may well have greater influence on other aspects of survey data quality such as nonresponse and possible nonresponse error.

Influences and Uses

There are currently no agreed upon standards of interviewer productivity because productivity can be influenced by so many characteristics of an interviewer-administered survey, including the survey mode (telephone, face-to-face), the survey population, the length of the questionnaire, the experience of the interviewer, and the particular phase of survey contact (initial contacts vs. callback attempts). The most frequently used measure of interviewer productivity is the number of completed interviews obtained by an interviewer during some set period of time, such as “per hour.” This is important to measure, as most surveys have a goal to achieve a specific number of completed interviews within a pre-specified field period length.

Interviewer productivity can be influenced by incentives added to their compensation. At least one study has found that the number of interviews an interviewer will complete during a shift can be affected by the offer of a monetary reward pegged to productivity. However, rewarding interviewers for productivity has potential drawbacks (e.g. interviewers may engage in cheating to earn monetary rewards), so this practice is generally frowned upon. Thus, whenever an incentive system is considered for rewarding interviewers for their productivity, it is critical that it be combined [Page 377]with a reliable and rigorous system of monitoring the interviewers.

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