Call Screening

Call screening is a practice in which many people engage whereby they listen to an incoming message on their answering machine or look on their caller ID to see who is calling before deciding whether or not to answer the call. This behavior is thought to negatively affect survey response rates. Over time, respondents have become increasingly unwilling to participate in surveys or even answer unsolicited telephone calls. This desire for privacy has resulted in legislation such as do-not-call lists and the use of a variety of technological barriers such as answering machines, caller ID, and call blocking to screen incoming calls. These screening devices allow individuals to determine which calls they will answer, making it more difficult for researchers to contact them. Further, individuals who always screen may also be more likely to refuse to participate if and when they are contacted.

More than two thirds of U.S. households have answering machines, and about 18% report always using their answering machine to screen calls. Telephone companies improved on the answering machine as a screening device with the development of caller ID technology. This service displays the caller's name and/or telephone number on a person's phone or caller ID device. It is estimated that more than half of all U.S. households now have caller ID and that nearly 30% always use it to screen calls. Call-blocking services that allow subscribers simply to reject certain numbers or classes of numbers are also growing in popularity.

Owners of these devices and those who regularly use them to screen calls have been shown to be demo-graphically different from the general population. It is not always easy to identify a screening household, particularly if the dialing always results in a noncontact. [Page 79]A number of approaches are being used by researchers in an attempt to improve contact with screening households. The most common approaches include mailing advance letters (when a phone number can be matched to an address), leaving a message on the answering machine, or transmitting the name of the research firm along with an 800 call-in number. However, when it comes to actually improving contact with these households, the results remain mixed.