Table 3.

Association between Attribution Status and Beneficiary Characteristics (40% Random Sample)

	Un-attributable to Provider Groups†
Variable	Marginal Effect	Std. Err.
Age	-0.001***	(0.00001)
Female	-0.045***	(0.0002)
Race Ethnicity
Black	0.047***	(0.0003)
Hispanic	0.052***	(0.0003)
Asian/Pacific Islander	0.035***	(0.0005)
Other Ethnicity	0.026***	(0.0006)
Lives in High Poverty (above 20 percent) Census Track	0.012***	(0.0002)
Dually Eligible	-0.042***	(0.0002)
Nursing Home Resident	-0.043***	(0.0010)
Disabled	0.045***	(0.0002)
Chronic Conditions-2011‡
Zero Observed Chronic Conditions	0.024***	(0.0003)
Non Healthcare Service User (Unknown Chronic Conditions)-2011	0.204***	(0.0002)
Unknown Chronic Condition History (New 2012 Fee-for-Service Medicare Enrollees and 2011 Managed Care Enrollees)-2011	0.223***	(0.0003)
Observations	12,852,274
Pseudo R-squared	0.220

Notes: A Logistic regression was estimated for the attribution measure. The marginal effects reported are the averages of marginal effects across the sample on the predicted probability of being unattributable.

Std. Err. Standard Error.

^†The outcome variable is a dichotomous variable for whether the beneficiary is unattributable to any provider group as opposed to being attributable to a provider group (either associated with a Medicare ACO or any other provider group). The coefficients represent the estimated marginal effects or changes in the predicted probability. HRR fixed effects are included. Standard errors are in parentheses.

^‡The reference category is the group of patients with one or more observed chronic conditions.

Inference: *** p<0.001,

^**p<0.01,

^*p<0.05.