Table 2.

Simulation study results: estimated readmission rates. The ‘true’ readmission rate was 8.8%

		NHS number error distribution in simulated data
		30%, random	0.5%, random	30%, associated with other identifier errors	30%, associated with ethnicity
Traditional match weight	% readmitted	7.4	7.4	6.9	7.4
	Standard error	0.002	0.002	0.002	0.002
	% bias	−15.9	−15.9	−21.3	−15.7
Match weight incorporating dependence	% readmitted	7.4	7.4	6.9	7.4
	Standard error	0.002	0.002	0.002	0.002
	% bias	−16.0	−16.0	−21.4	−15.8
Attribute-specific match weight	% readmitted	8.7	8.7	8.7	8.8
	Standard error	0.002	0.002	0.002	0.002
	% bias	−0.6	−0.6	−0.9	−0.2
Organisation-specific match weight	% readmitted	8.8	8.8	8.8	8.8
	Standard error	0.002	0.002	0.002	0.002
	% bias	0.2	0.2	−0.1	0.2