Table 4:

The Influence of Payments on Prescription Volume, Different Peer Definitions

	Dependent Variable: Number of Prescribed Patients
	(1)	(2)	(3)
Compensation Payment Count, by Recipient Type:
Own	0.3684 (0.1156)	0.3684 (0.1155)	0.3679 (0.1156)
Shared-Patient Peer	0.0197 (0.0061)	0.0284 (0.0077)	0.0221 (0.0061)
Below-Median Shared-Patient Peer		−0.0200 (0.0093)
Group Practice and Shared-Patient Peer			−0.0091 (0.0145)
Group Practice and not Shared-Patient Peer			0.0134 (0.0045)
N (Doctor×Drug×Quarter)	5,466,420	5,466,420	5,466,420

Notes: Estimates of equation (2). The dependent variable is the number of prescribed patients. Independent variables capture the counts of exposure to compensation payments, for different types of recipients. “Own” denotes payments to the prescribing physician. “Shared-Patient Peer” denotes a payment recipient with whom the prescriber shared at least 11 Medicare patients. “Below-Median Shared-Patient Peer” denotes a payment recipient with whom the prescriber shared less than 21 patients (the median number for our sample), a proxy for a weaker relationship. “Group Practice and Shared Patients Peer” coefficients report the difference in payment impact for those with both group practice and shared-patient ties, relative to those with only shared-patient ties. Finally, the “Group Practice Peer and not Shared-Patient Peer” coefficient reports the impact of payments to peers who share a group practice affiliation but do not meet the definition of a shared-patient peer. See Section 1 for exact definitions. Physician-drug, specialty-drug-quarter fixed effects, controls for all other types of payments, and payment-type-specific linear time trends included in all specifications. Standard errors are clustered within doctor.