Appendix Table 2.

Consistency of BI-RADS Density Categories and Population Categorization

Study Time between assessments	Study sample inclusion criteria	Assessments	a* (%)	b† (%)	c‡ (%)	d§ (%)
Harvey, 2013 (20) <36 mo	Women aged 40 years and older, with no history of breast cancer or reported use of hormone therapy at the time of exam or during the previous year, and had two or more screening mammographic examinations less than 36 months apart between January 1, 2000, and December 31, 2009 (n=435,751)	Exam 1	9.4	45.2	37.9	7.5
		Exam 2	10.2	45.1	37.2	7.2
Spayne, 2012 (24) 3–24 mo	Women who were postmenopausal‖, with no history of breast cancer or reported use of hormone therapy, and had two or more film-screen screening or bilateral diagnostic mammograms including BI-RADS breast density assessments between January 1, 1996 and December 31, 2006 (n=11,755)	Exam 1	9.8	61.0	26.6	2.5
		Exam 2	9.2	60.2	28.1	2.5
Gard, 2015 (23) 6 mo	Women contributing examinations to the test set had a screening mammogram interpreted in the health care system between 1996 and 1998 and were enrolled in the system for at least 2 years following screening; the test set was designed to include about twice as many examinations of women with cancer as without, and roughly equal numbers of non-dense and dense examinations based on clinical interpretation (n=341)	Reading 1¶	6.1	44.3	38.3	11.4
		Reading 2#	4.5	39.2	47.0	9.3

^*Breast density category a = almost entirely fat

^†Breast density category b = scattered fibroglandular densities

^‡Breast density category c = heterogeneously dense

^§Breast density category d = extremely dense

^‖Aged 55 years or older or reported having experienced natural menopause, having had both ovaries removed, or having more than 365 days elapse since their last menstrual period

^¶Clinical interpretation of exams prior to inclusion in test set

^#Based on BI-RADS classification by the majority of readers for each exam in the test set

Abbreviations: BI-RADS=Breast Imaging-Reporting and Data System; mo=months