Cold Call

A cold call refers to the circumstance that takes place in many surveys when a respondent is first called or contacted in person by a survey interviewer without any advance knowledge that he or she has been sampled to participate in the survey, and thus does not know that the call or contact is coming. This circumstance contrasts to other instances in which some form of advance contact has been made with the sampled respondent to alert him or her—that is, to “warm up” him or her—that he or she has been sampled and that an interviewer soon will be in contact. Survey response rates consistently have been found to be lower for those sampled respondents that receive cold calls than for those that receive advance contact.

For many people who are sampled in telephone surveys, there is no way that researchers can use an advance mail contact technique because all that is known about the sampled household is the telephone number. This occurs even after the researchers have run matches of sampled telephone numbers against address databases and no address match is identified. Granted, an advance telephone contact attempt could be made in which a recorded message is left alerting the respondent that he or she has been sampled for a survey and that an interviewer will call him or her within a few days. However, there is no reliable evidence that this approach ever has been found to be effective. Instead the concern is that such a telephonic advance contact will lower response propensity at the given telephone number when the human interviewer eventually makes contact.

Despite this concern, the argument can be made that advance telephone contacts that merely leave a recorded message that a household has been chosen for a survey are not dissimilar to instances in which interviewers reach an answering machine the first time they call a household and leave a message saying that they will be calling back to conduct a survey. Past research has found that these types of answering machine messages tend to raise response rates. As such, even with households that cannot be mailed an advance contact, the proportion that receives cold calls for telephone surveys can be greatly reduced.

With face-to-face interviewing in address-based sampling or area probability sampling, all sampled households can be mailed an advance contact because, by definition, the researchers know their addresses. Thus, in such surveys there are no structural barriers that make it impossible to avoid any household receiving a cold contact from the in-person interviewer when he or she arrives the first time to recruit the household and/or gather data.