Random Digit Dialing: A Comparison to Personal Surveys

This article reports on the replication of a large, personal interview survey by means of a random digit dialing telephone survey. The personal interview survey was based on a complex probability sample of Cincinnati households with the field work being done by the Census Bureau during early 1974. The telephone replication was done immediately afterwards. The objective was to test the accuracy and efficiency of random digit dialing telephone surveys in comparison to the best traditional alternative. The samples were compared on demographic characteristics, measures of crime victimization, and attitudes toward crime and the police. The results were very similar, indicating that random digit dialing is an accurate and cost-effective alternative to traditional personal interviewing surveys for most research applications. William R. Klecka is a Senior Research Associate at the Behavioral Sciences Laboratory and Associate Professor of Political Science at the University of Cincinnati. During the writing of this article he was a Visiting Scholar at Northwestern University's Center for Urban Affairs. Alfred J. Tuchfarber is Director of the Behavioral Sciences Laboratory at the University of Cincinnati. The authors wish to thank the staffs of the Behavioral Sciences Laboratory and the Center for Urban Affairs for their assistance, and the Police Foundation of Washington, D.C. for their generous support of this project. Public Opinion Quarterly (? ) 1978 by Columbia University Published by Elsevier North-Holland, Inc. 0033-362X/78/0042-0105/$01.25 This content downloaded from 157.55. 39.136 on Tue, 05 Jul 2016 04:36:42 UTC All use subject to http://about.jstor. org/terms 106 KLECKA AND TUCHFARBER telephone as an interviewing method (for example, Rogers 1976) have been published. Several panels on telephone surveys have been held at recent professional meetings. The primary reasons for the increased use of telephone surveys are financial pressures and technological changes. Increasing salaries and rising fuel costs have conspired to make personal interviewing surveys extremely costly because of the travel involved. Finding the desired respondent at home has also become increasingly difficult, particularly because of the increased labor force participation of married women. How much RDD can save depends upon the particular study. One example worked out by Tuchfarber and Klecka (1976:18-20) shows that field work and sampling costs in RDD may be as little as 20 percent to 25 percent of those for personal interviewing. Improvements in telephone equipment have also made telephone interviewing easier. But the most important justification is that telephones are now more ubiquitous. In 1958, only 72.5 percent of U.S. households had access to a telephone either in their own dwelling unit or elsewhere. By 1965, this figure was still a low 80.6 percent, but for 1970 it rose to 86.7 percent and then reached 92.8 percent in 1976.1 Clearly, a researcher of 10 or 20 years ago should have hesitated to employ a sampling technique which inherently excluded a fourth of the population. Now that telephone surveys can encompass more than nine-tenths of the population, we can feel less concerned that the biases due to coverage problems will grossly distort our results.2 The question still remains whether the exclusion of nontelephone households and/or the use of telephones as a medium of communication seriously reduce the accuracy of RDD surveys. This article will reDort on the first major experiment3 designed to directly compare the I See U.S. Dept. of Commerce (1958, 1965). The 1970 figure was computed from the Public Use Sample tape (1 in 10,000 sample) derived from the 1970 Census of Housing and Population. The 1976 statistics were computed from the January through June panels (N=59,861 households) of the National Crime Survey conducted by the U.S. Bureau of the Census on behalf of the Law Enforcement Assistance Administration (LEAA). Telephone availability can be broken down between "own home" and "elsewhere" only for the 1976 data. In that year, 90.2 percent of the households had phones in their own homne. 2 William R. Klecka and A. Elizabeth Powell have been using the massive National Crime Survey data collected by the Census Bureau for the LEAA to identify sources of potential bias in telephone surveys. Their approach has been to compare households with a telephone to the total sample. The differences have been extremely sinall on both demographic and behavioral items. A preliminary report has been presented (Powell and Klecka, 1976), and some of the data also appear in Tuchfarber and Klecka (1976:20-28). The 1976 data show that the conditions for RDD surveys are much more favorable than implied by the 1970 Census data reported in Tull and Albaum (1977). When considering the potential bias in RDD surveys, one should remember that the tiny proportion of persons without telephones cannot all be reached by personal survey methods either. Persons without telephones tend to be transients and/or social isolates. These individuals are very difficult to reach regardless of which survey method is used. (Also see Leuthold and Scheele, 1971). 3Subsequent to this project, the University of Michigan's Survey Research Center did a replication of their Spring 1976 Omnibus Survey with random digit dialing. This content downloaded from 157.55. 39.136 on Tue, 05 Jul 2016 04:36:42 UTC All use subject to http://about.jstor. org/terms RDD AND PERSONAL SURVEYS 107 results of an RDD survey to those derived from a personal interview survey based on a traditional area-probability sample.4 Specifically, it tests the hypothesis that random digit dialing telephone surveys are an efficient, accurate, and inexpensive alternative to most face-to-face interviewing applications.