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On-Line vs. Phone Surveys: Comparison of Results for a Bicycling Survey


Research Report

Sustainable Transportation Center, BicyclingPlus Research Collaborative

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Suggested Citation:
Xing, Yan and Susan L. Handy (2011)

On-Line vs. Phone Surveys: Comparison of Results for a Bicycling Survey

. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-11-24

Researchers in the transportation field rely heavily on the traditional random-digit dialing phone survey and increasingly on on-line surveys. Many studies have looked at the strengths and weaknesses of the two survey methods with respect to the representativeness of the resulting sample as well as descriptive differences in responses to the survey questions. However, few of them have examined the inferential differences between the survey methods, for example, by comparing the coefficients of models of travel behavior estimated for each sample separately, to assess the degree to which the models yield consistent conclusions. In this paper we compare both descriptive and inferential results from on-line and phone surveys with identical questions conducted in Davis, CA. A split-sample approach was employed to examine the performance of models developed from the on-line survey data.  Results show that although bicycling behavior does not differ across the two survey samples, many socio-demographic characteristics do.  The models developed from each sample have several statistically indistinguishable coefficients but also notable differences in key explanatory factors.  In addition, the models of bicycling behavior estimated with on-line data do not do a good job of predicting bicycling behavior as measured in the phone survey.  Thus, the two survey methods in this case lead to different inferential results with different policy implications.