. Author manuscript; available in PMC: 2018 May 11.

Published in final edited form as: Rev Econ Stat. 2018 Mar 2;100(1):29–44. doi: 10.1162/REST_a_00670

Table 3.

Author Proximity Effect on Drug Utilization Dependent Variable: New Drug Use

Proximity Measures	A. All HRRs		B. Author HRRs Only		C: New Cancer Patients
	(1)	(2)	(3)	(4)	(5)	(6)
First author HRR	0.0404^*** (0.0131)		0.0383^*** (0.0122)		0.0399^*** (0.0154)
Other author HRR	0.0069 (0.0048)		0.0068 (0.0051)		0.0059 (0.0053)
First author HRR and in author group		0.0421^*** (0.0125)		0.0417^** (0.0124)		0.0421^*** (0.0162)
First author HRR and nonauthor group		0.0416^** (0.0211)		0.0392^** (0.0195)		0.0409^** (0.0203)
Other author HRR and in author group		0.0276^*** (0.0074)		0.0286^*** (0.0073)		0.0271^*** (0.0082)
Other author HRR and nonauthor group		−0.0031 (0.0054)		−0.0033 (0.0058)		−0.0036 (0.0057)
Number of observations	659,468	659,468	286,637	286,637	393,618	393,618

This table reports results from six separate regressions, where the dependent variable is an indicator that equals 1 if the patient is treated with the new drug over the observed episode of care. Each observation is a patient episode: a one-year episode of cancer treatment. The sample includes all episodes of care for the relevant cancer type within two years following a drug’s FDA approval. “First author HRR” (hospital referral region) is an indicator variable that equals 1 if the patient is treated in the same HRR as the trial’s first author. “Other author HRR” indicates treatment in the same HRR as another trial author (but not the first author). Author physician group indicators equal 1 if the patient was at any point during the year treated by a physician practicing in the same group as a trial author. All regressions include drug-year fixed effects; HRR-cancer-type fixed effects defined using three categories of cancer drugs: urologic, hematologic, and other (including breast, colon, lung, and brain); and indicators for patient age, race, sex, and new cancer treatment episode. Standard errors clustered at the HRR-drug level shown in parentheses.

Significant at *p < 0.10, **p < 0.05, and ***p < 0.01.

Columns 1 and 2: All HRRs and patient episodes within two calendar years after drug’s FDA approval. Columns 3 and 4: Sample limited to HRRs containing any pivotal trial author. Columns 5 and 6: All HRRs but limited to new cancer patients, defined as patients with no cancer treatment in previous calendar year.