TABLE 1.

Characteristics of the Study Population

	Faculty						P-value for Comparison by Sex*
	All (n = 3810)		Male (n = 3180)		Female (n = 630)
	Count	%	Count	%	Count	%
Faculty Rank
Assistant	1866	49.0	1487	46.8	379	60.2	<0.001
Associate	871	22.9	720	22.6	151	24	0.47
Full	1073	28.2	973	30.6	100	15.9	<0.001
Sub-Specialty†
Non-Invasive‡	2598	68.2	2057	64.7	541	85.9	<0.001
Electrophysiology	497	13.0	443	13.9	54	8.6	<0.001
Interventional Cardiology	715	18.8	680	21.4	35	5.6	<0.001
Faculty at Top 20 Med School§	1248	32.8	1015	31.9	233	37.0	0.02
Age (SD)	52.7	11.6	53.5	11.8	48.3	9.4	<0.001
Age Groups
Age <40	526	14.2	404	13.4	122	20.4	<0.001
Age 40–44	582	15.8	463	14.9	119	19.9
Age 45–49	497	13.5	395	12.8	102	17.1
Age 50–54	537	14.5	439	14.2	98	16.4
Age 55–59	483	13.1	404	13.0	79	13.2
Age 60–64	464	12.6	411	13.3	53	8.9
Age 65+	607	16.4	583	18.8	24	4.0
Years since Residency||	22.2	12.0	23.1	12.2	17.6	9.4	<0.001
Publications
Total (SD)	23.8	36.7	25.2	38.2	16.5	27.5	<0.001
First/Last Author (SD)	15.2	28.9	16.4	30.5	9.5	18.2	<0.001
NIH Grants
At least one	399	10.5	331	10.4	68	10.8	0.77
Median, at least one (25–75 pctile)	4	2–9	4	2–9	3	1–7	0.08
Clinical Trials
At least one	410	10.8	354	11.1	56	8.9	0.10
Median, at least one (25–75 pctile)	1	1–2	1	1–2	1	1–2	0.65
Total Medicare Payments, 2013--$ (SD)	91,674	101,150	95,902	106,295	70,258	65,470	<0.001

Abbreviation: NIH= National Institutes of Health

^*P values reflect 2-sided t tests and X² comparisons where appropriate. P value for age reflects comparison of age distributions.

^†Sub-specialty classification was based on American Board of Internal Medicine (ABIM) sub-specialty board certification.

^‡All cardiologists without ABIM certification in electrophysiology or interventional cardiology.

^§Top 20 school refers to whether a physician was on faculty at a medical school ranked among the top 20 US medical schools for research by US News & World Report in 2013.¹⁵

^||Calculations excluded 287 cardiologists for whom data on years since residency was unavailable.