Table 3.

Performance of the Models in Explaining Concurrent Utilization (FY ‘97)

Risk Adjustment Model	Number of Parameters	Service Days R2	Ambulatory Provider Encounters R2	Mental Health/Substance Abuse Service Days R2
		n = 1,046,803	n = 1,039,712	n = 1,046,803
Model 1: Standard DCG/HCC Model + Age/Gender	135	0.3153	0.2458	0.1810
Model 2: Model 1 + 3 SA Indicator Variables (Patients with mild/moderate SA in HCCs 32, 33 and 35)	138	0.3155	0.2464	0.1813
Model 3: Model 1 + 5 SA Indicator Variables (Patients with severe SA in HCC 31 divided into 5 groups: alcohol only; drugs only; alcohol & drugs; alcohol, drugs & mild/moderate abuse; alcohol & mild/moderate abuse; drugs & mild/moderate abuse)	140	0.3236	0.2778	0.2002
Model 4: Model 1 + SA Indicator Variables from Models 2 and 3	143	0.3238	0.2785	0.2005

Note: Utilization outcomes were annualized based on the number of months a patient was alive during the 12-month period. Ambulatory provider encounters=the number of “face-to-face” provider-related ambulatory encounters in FY ‘97 based on the individual clinic stop plus Evaluation and Management (E/M) CPT-4 codes. Service days=sum of the number of ambulatory visit days and number of inpatient days in FY’97 (maximum=365 days). MH/SA Service days=sum of the number of ambulatory MH/SA visit days + number of inpatient days in FY ‘97 in a MH/SA bedsection (maximum=365 days).