Table 2.

Risk Ratios (RR), Standard Error (SE), and 95% Confidence Intervals (CI) obtained using the Across approach and the Within approach on BSRBR Data

	The Across approach			The Within approach
	RR	SE	95% CI	RR	SE	95% CI
Stratification	0.778	0.126	0.566, 1.069	1.001	0.167	0.722, 1.387
IPTW	0.782	0.170	0.510, 1.197	0.785	0.175	0.507, 1.215
Matching	0.920	0.173	0.637, 1.330	1.049	0.230	0.678, 1.622
SMRW	0.781	0.188	0.486, 1.250	0.744	0.191	0.449, 1.230

Abbreviations: IPTW, inverse probability of treatment weighting; SMRW, standardized mortality ratio weighting.