Using Advance Respondent Letters in Random-digit-dialing Telephone Surveys

The rationale for the use of an advance respondent letter is based on the experience of survey researchers that contact before an actual interview attempt “warmsup” respondents, hopefully making them more positively disposed toward participation than if they were only to receive a “cold call.” The logic is that using advance respondent letters will increase response rates, thereby reducing the potential size of nonresponse-related total survey error. For example, Traugott, Groves, and Lepkowski (1987) reported an experiment in which advance contact in a telephone survey of the public increased response rates by 10 percentage points. To the extent that advance letters reduce nonresponse, they also are likely to be highly cost effective by decreasing the need for far more expensive refusal conversion attempts (Frey, 1989; Lavrakas, 1993). For the typical RDD telephone survey, the first attempt made to contact a household is always a “cold call.” Since numbers are randomly generated, the person who answers the telephone does not expect the call, and may have never heard of the government agency sponsoring the survey or the survey organization collecting the dam. This lack of familiarity is one reason that RDD surveys typically achieve lower response rates than face-to-face household surveys. Another problem in RDD surveys is the proportion of individuals who simply hang up during the introduction without saying anything (HUDIs), often as soon as the interviewer begins to speak. Wulfsberg and Battaglia (1992), and Traugott, Groves, and Lepkowski (1987) discuss the potential for increasing response to surveys by using an advance respondent letter combined with RDD sampling methodology. To obtain addresses that correspond to the RDD-generated telephone numbers, a file containing the RDD-generated telephone numbers is crossreferenced against a computerized database containing directory-listed residential telephone numbers, names, and addresses. It is possible that an advance letter may unintentionally increase both total survey error and survey costs. If potential survey respondents learn from advance contact what makes one ineligible or eligible to be interviewed, some may answer the survey’s screening sequence inaccurately so as to avoid being interviewed. If this occurs, the potential respondent is actually refusing to participate and will be incorrectly coded as ineligible. Conversely, if potentially eligible survey respondents are not sufficiently persuaded as to the benefits that will accrue through survey participation, or if they do not see the relevance of the survey topic to their own circumstances, they may refuse to participate. An appeal to potential respondents to screening surveys that is too weak could possibly result in lower than predicted eligibility rates, since eligible respondents may participate at lower rates than ineligible households, especially since it is much easier to screen out ineligible households than enlist eligible households to participate.