Table 3.

Bias analysis for eight imputed models as well as the reference model when detecting postoperative SSI. The average AUC and bias across the three sub-types of SSI and overall SSI are calculated as well.

	Superficial SSI		Deep SSI		Organ Space SSI		Overall SSI
	AUC	Bias	AUC	Bias	AUC	Bias	AUC	Bias	Average AUC	Average Bias
Reference	0.855	0.0600	0.702	−0.0032	0.864	−0.0136	0.864	−0.0159	0.821	−0.0079
Mean	0.841	0.0131	0.864	−0.0085	0.867	−0.0086	0.863	−0.0055	0.858	−0.0024
Normal	0.845	0.0132	0.866	−0.0014	0.896	−0.0092	0.935	0.0038	0.884	0.0016
MICE	0.832	0.0191	0.865	−0.0010	0.894	−0.0087	0.927	0.0053	0.879	0.0037
0	0.852	0.0122	0.886	−0.0090	0.903	−0.0105	0.934	−0.0072	0.893	−0.0036
Dummy+Mean	0.851	0.0155	0.823	−0.0155	0.935	−0.0088	0.906	0.0052	0.878	−0.0009
Dummy+Normal	0.856	0.0155	0.844	−0.0009	0.934	−0.0082	0.926	0.0052	0.888	0.0029
Dummy+MICE	0.843	0.0195	0.826	0.0001	0.946	−0.0082	0.903	0.0089	0.879	0.0051
Dummy+0	0.724	0.1679	0.813	−0.0154	0.774	0.1349	0.655	0.0639	0.741	0.0879