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Title Determining the Probability of Selection for a Telephone Household in a Random Digit Dial Sample Design is Becoming more Difficult
Year 2003
Access date 20.04.2013

When surveys first starting using random digit dial (RDD) sample designs the vast majority of telephone households had only one telephone number. What has been occurring over time is an increase of telephone numbers assigned to households relative to the total number of telephone households. This change has occurred because more households now have separate phone numbers for computers, fax machines, and home businesses. Complicating this issue is that many households use these additional telephone numbers for multiple purposes. Further complicating the estimates of home phone numbers is the recent dramatic increase in usage of cell phones. While RDD sample designs usually do not include cell phones, the call forwarding features and respondent self reports of phone line usage makes it very difficult to correctly identify the number of residential phone numbers in a household. For many years, researchers using a RDD sample design could estimate the total number of residential telephone numbers in a household by simply asking one, sometimes two, and at most three questions. The 2002 National Survey of America's Families (NSAF) is telephone survey that relies primarily on a large RDD sample design using over 400,000 telephone numbers. In previous rounds of the NSAF (1999 and 1997) the simple two question approach was used to estimate total residential phone numbers that could be sampled. For the 2002 study a more complex set of questions was asked in each household that included learning more about what these additional phone numbers were being used for. This research will compare the results of these questions with other large RDD studies, compare with the previous NSAF rounds and discuss the impact these questions have on the probability of selection adjustments.

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Year of publication2003
Bibliographic typeConferences, workshops, tutorials, presentations