Telephone appends for address-based samples—An introduction

Surveys with samples selected from an address frame derived from US Postal Service sources are often referred to as address-based sampling (ABS) surveys. For an ABS survey that is primarily conducted by mail, web, or face-to-face, sometimes it is helpful to have a telephone number corresponding to the sample addresses for setting appointments or conducting nonresponse follow-up prompts. The usefulness of a telephone contact mode in a mixed mode ABS design depends on both the percentage of addresses for which telephone numbers can be appended (append rate or match rate) and the accuracy of the telephone numbers associated with addresses. Before planning a telephone contact as part of a mixed-mode study, the designer should know the likely effectiveness of the approach. This paper focuses primarily on append rate information, with a discussion of accuracy rates. For a single ABS frame, telephone match rates vary by geography, address type, match vendor, and by landline vs. cell telephone number. Using very large samples of addresses from a total US ABS frame, we estimated state and national telephone append rates from Marketing Systems Group's sources. The append rates are summarized here and interactively at the website http://abs.rti.org/atlas/.