Unpacking analyses relying on area-based data: are the assumptions supportable?

Table 7 Residents of Perth admitted to hospital, 1994–1998, by socioeconomic disadvantage of area for selected area levels

Quintile	Individuals admitted			Separations
	CD	Postcode	SLA	CD	Postcode	SLA
	Number
Q1: Least disadvantaged	126 615	123 380	138 127	294 130	303 131	340 294
Q2	130 907	123 465	114 244	294 307	326 652	279 537
Q3	133 073	126 770	142 107	316 066	328 999	363 908
Q4	124 279	128 863	123 199	327 228	328 630	313 879
Q5: Most disadvantaged	142 704	155 100	139 901	433 577	377 896	367 690
Total	657 578	657 578	657 578	1 665 308	1 665 308	1 665 308
	Rate (per 100 000 population)
Q1: Least disadvantaged	51 442	48 247	51 950	119 813	120 567	127 986
Q2	53 343	48 239	52 235	120 582	129 945	127 810
Q3	53 889	48 789	52 656	127 995	126 618	134 841
Q4	50 919	51 263	52 564	133 342	128 400	133 920
Q5: Most disadvantaged	58 130	61 691	58 491	176 157	147 734	153 728
Total	53 547	53 547	53 547	135 607	135 607	135 607
Rate ratio: Ratio of rate in Q5 rate in Q1	1.13***	1.28***	1.13***	1.47***	1.23***	1.20***

The extent of any inequality is shown by the rate ratio, which expresses the ratio of the rate in Quintile 5 to the rate in Quintile 1; rate ratios indicating differing significantly from 1.0 are shown with * p < 0.05; ** p < 0.01; *** p < 0.001.

ISSN: 1476-072X