title: Estimating screening-mammography receiver operating characteristic (ROC) curves from stratified random samples of screening mammograms: a simulation study.
abstract: OBJECTIVE
  To evaluate stratified random sampling (SRS) of screening mammograms by (1) Breast Imaging Reporting and Data System (BI-RADS) assessment categories, and (2) the presence of breast cancer in mammograms, for estimation of screening-mammography receiver operating characteristic (ROC) curves in retrospective observer studies.
  
  
  METHODS
  We compared observer study case sets constructed by (1) random sampling (RS); (2) SRS with proportional allocation (SRS-P) with BI-RADS 1 and 2 noncancer cases accounting for 90.6% of all noncancer cases; (3) SRS with disproportional allocation (SRS-D) with BI-RADS 1 and 2 noncancer cases accounting for 10%-80%; and (4) SRS-D and multiple imputation (SRS-D + MI) with missing BI-RADS 1 and 2 noncancer cases imputed to recover the 90.6% proportion. Monte Carlo simulated case sets were drawn from a large case population modeled after published Digital Mammography Imaging Screening Trial data. We compared the bias, root-mean-square error, and coverage of 95% confidence intervals of area under the ROC curve (AUC) estimates from the sampling methods (200-2000 cases, of which 25% were cancer cases) versus from the large case population.
  
  
  RESULTS
  AUC estimates were unbiased from RS, SRS-P, and SRS-D + MI, but biased from SRS-D. AUC estimates from SRS-P and SRS-D + MI had 10% smaller root-mean-square error than RS.
  
  
  CONCLUSIONS
  Both SRS-P and SRS-D + MI can be used to obtain unbiased and 10% more efficient estimate of screening-mammography ROC curves.
authors: Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, MC2026, Chicago, IL, 60637. Electronic address: richard.zur@sickkids.ca.
authors: Richard M
authors: RM
authors: Zur
authors: Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, MC2026, Chicago, IL, 60637.
authors: Lorenzo L
authors: LL
authors: Pesce
authors: Department of Radiology, The University of Chicago, 5841 South Maryland Avenue, MC2026, Chicago, IL, 60637.
authors: Yulei
authors: Y
authors: Jiang
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods*; D008403:Mass Screening; D009010:Monte Carlo Method; D012372:ROC Curve; D012189:Retrospective Studies
keywords: ROC analysis; Screening mammography; observer studies; simulation study; stratified random sampling