The All Patient Refined Diagnosis Related Group - Text Mining Techniques for Healthcare Provider Quality Determination - page 221

Figure 18. Variable definitions
Figure 19. Predictive model to predict the APRDRG
APRDRG severity index and the Charlson Index. This analysis shows that there is a lack of consistency
in assigning levels of severity.
Figure 22 gives one branch of the corresponding decision tree. Age, charges, and length of stay are
used as classifiers before the introduction of the Charlson Index in branch 3.