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