Figure 3. Sampling Structure.

Health district refers to local health district in New South Wales, hospital health service in Queensland, and local health network in South Australia. GP indicates general practitioner.

^aMetropolitan and regional strata are geographically defined; tertiary pediatric hospitals were sampled outside of this classification as they have statewide responsibility; and 5 of the 6 tertiary hospitals were physically located within metropolitan strata.

^bNumber of health districts or tertiary hospitals selected; 1 of the 6 tertiary pediatric hospitals was located within a selected health district.

^cNumber of sites of each type successfully recruited within the metropolitan or regional strata or among the tertiary pediatric hospitals.

^dFive excluded, 4 ineligible due to lack of a hospital with sufficient patient volumes, 1 excluded due to remoteness; together comprise 7.5% of regional population aged 15 years and younger.

^eOne excluded as ineligible due to lack of a hospital with sufficient patient volumes; 32.2% of metropolitan population aged 15 years and younger.

^fTwo health districts were randomly selected in regional Queensland initially. One, which contained 2 eligible hospitals, was removed because neither hospital responded to recruitment efforts; 2 other districts, each containing 1 eligible hospital, were nonrandomly selected to replace the lost district.

^gThe study was unable to recruit any pediatricians in the eligible health districts in South Australia; all 8 pediatricians were therefore recruited from a health district that was not eligible for selection because it lacked a hospital with the required patient volumes.