Table 2.

Table 2 Confusion Matrices (2×2 Tables) for Original Rule and New Rules that Incorporate “Epidemiological Context Adjustor”

Original Rule (no adjustment for epidemiological context)
Actual	Predicted
	Aseptic	Bacterial	Total
Aseptic	384	151	535
Bacterial	2	117	119
Total	386	268	654
Sensitivity 98%, Specificity 72%.

Sample Rule A (2 cases in previous 6 days)
Actual	Predicted
	Aseptic	Bacterial	Total
Aseptic	433	102	535
Bacterial	3	116	119
Total	436	218	654
Sensitivity 97%, Specificity 81%.

Sample Rule B (8 cases in 4 previous days)
Actual	Predicted
	Aseptic	Bacterial	Total
Aseptic	384	151	535
Bacterial	2	117	119
Total	386	268	654
Sensitivity 98%, Specificity 72%.

Sample Rule C (4 cases in previous 10 days) – Best Rule
Actual	Predicted
	Aseptic	Bacterial	Total
Aseptic	431	104	535
Bacterial	2	117	119
Total	433	221	654

Sensitivity 98%, Specificity 81%.