Appendix Table A3.

Results from the sensitivity checks

	Instrumental Variables (IV) analysis
	Estimate (Robust Standard Error)
Outcomes	% of visits integrated oncologists†	Including patients who died during the year‡
Utilization
Log(Frequency of chemotherapy drug claims)	−0.08(0.03)***	−0.07(0.03)**
Log (Frequency of chemotherapy administration claims)	−0.06(0.03)**	−0.06(0.03)**
Spending ($)
Log Chemotherapy drug spending)	0.19(0.06)***	0.19(0.05)***
Log(Chemotherapy administration spending)	0.09(0.05)*	0.07(0.04)*
Treatment mix
Log(Chemotherapy drug spending per claim)	0.27(0.05)***	0.26(0.04)***
First-Stage Statistics
Estimate on instrument (Robust Standard Error)	0.66(0.01)***	0.70(0.01)***
F-Statistic	3,993	4,067
N	81,899	101,622

Notes: Oncologist fixed effects are included. Covariates controlled for in all models are patient demographic characteristics, chronic condition indicators, cancer type, metastasis indicator, and ZIP-level socio-economic variables; Spending measures are adjusted to 2013 dollars; Standard errors account for clustering by practice in all models;

^†Integration is measured by the share of total visits to an integrated oncologist;

^‡This sample is different from the primary analysis, which requires the patients to have full-year enrollment in both Part A and Part B;

^*p < 0.10,

^**p < 0.05,

^***p < 0.01.