Does sampling using random digit dialling really cost more than sampling from telephone directories: Debunking the myths

Table 4 Comparison of number of dialling, calling time and cost for an assumed electronic white pages sample to achieve the same precision of estimates from an assumed effective sample size of 1,000 (equivalent of a simple random sample size 1,000)

	Average sample (design effect ratio = 1.19)		High psychological distress (design effect ratio = 1.32)
	LA-RDD n = 2,000	EWP n = 2,380	LA-RDD n = 1,960	EWP n = 2,600
Number of dialling	29,800	23,562	29,204	25,740
Costed dialling *	16,600	15,708	16,268	17,160
Calling time (in hours)	1,180	1,249.5	1,156.4	1,365
Cost†	$26,920	$28,132	$26,382	$30,732

* excluding dialling of not connected numbers and dialling with no answer
† The costs is calculated as: A$0.20 × number of costed dialling + A$20 × number of calling hours.
Source: New South Wales Health Survey Program, Centre for Epidemiology and Research, New South Wales Department of Health.

ISSN: 1471-2288