Table 2: APACHEII and APACHE IV Predicted Outcome vs. Observed Outcome Cross Tabulation

Outcome Total
Non-survival (N) Survival (N)
APACHE II Prediction Non-survival 90 19 109
Survival 81 61 142
APACHE IV Prediction Non-survival 89 19 108
Survival 82 61 143
Observed 171 80 251

Observed mortality rate 68.1
APACHE II predicted mortality rate 43.4%
APACHE IV predicted mortality rate 43%
APACHE II: Sensitivity=52.6%, Specificity=76.3%, Cut off value=24.5
APACHE IV: Sensitivity=52%, Specificity=76.2%, Cut off value=90.5