Table 3.

Calculation for establishing the required sample size, assuming the worst case scenario for each adverse event (AE) indicator

Adverse event (AE) indicator	Worst case scenario a
	AE positive	AE negative b
Nosocomial pneumonia (NP)	237	3,099
Central venous catheter-associated blood stream infection (CVC-BSI)	237	3,099
In-hospital fall	165	2,161
Total	639	3,099
Total number of charts to be reviewed if worst case scenario	3,738

^aBased on optimal sample sizes provided in Table 2 (see values in italics). ^bTo minimize the costs associated with performing chart review, all AE negative patients will be selected so that they are negative for all three AEs according to the automated detection algorithms. As such, 3,099 is the largest number of AE negative patients required, assuming the worst case scenario.