A cohort of cases from the Breast Pathology Study (B-Path) was used for this analysis. The methods for test case identification and the development and recruitment of pathologists have been previously described (3 (link), 7 (link)). Briefly, single, representative diagnostic slides from excisional or core breast biopsies of 180 women were included in this pilot study. Each slide was digitally scanned (iScan Coreo, Ventana Medical Systems, Tucson, AZ), and a whole slide image (WSI) was created, allowing the digital virtual slide to be viewed, magnified, and annotated on a computer using a web-based viewer.