How different is a random digit dialing sample from a listed sample?
In Canada, about 98% of all households have telephones, and unlisted telephone numbers are relatively rare. Given this, BUM has recruited participants for its radio ratings surveys using a sample frame of listed telephone numbers. In analyses of our typical sample profile, we have found that we tend to under-represent young, mobile, urban groups, the unemployed, students and those with lower income and education levels. We tested random digit dialing (RDD) in an attempt to improve representation of these groups. The differences between the RDD sample and a listed sample, however, seem to be quite small in the Canadian context. This paper compares an RDD sample with a listed sample, looking at demographic breakdowns, return rates, and tuning.
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