Defining the objectives, scope, and policy context of a model (here, six models): Effects of mammography screening under different screening schedules [7]

Decision problem/decision objective	To evaluate US breast cancer screening strategies.
Policy context	This analysis was used to inform the 2009 US Preventive Services Task Force recommendations on breast cancer screening.
Funding source	AHRQ, NCI
Disease	Breast cancer: Four models included ductal carcinoma in situ, two did not; cancer was characterized by estrogen receptor status, tumor size, and stage in all models and by calendar year in three.
Perspective	Stated as societal. Health outcomes are breast cancer outcomes for patients. Limited modeling of resources used (see below). The US Preventive Services Task Force does not consider costs in making its recommendations.
Target population
	Cohort of US women born in 1960. Subgroups were defined by age and the disease characteristics noted above. Subgroups mentioned in the report but not analyzed: BRCA1 and BRCA2, black, comorbidities, HRT, obese.
Health outcomes
	Reduction in breast cancer deaths and life-years gained, false-positive results, overdiagnosis. Explicitly not included: morbidity from unnecessary biopsies or from treatment.
Strategies/comparators
	Screening: Twenty mammography screening strategies defined by frequency (annual or biennial), starting age (40, 45, 50, 55, or 60 y), and stopping age (69, 74, 79, or 84 y); no screening. Assumed 100% compliance.
	Follow-up treatment: ideal and observed patterns.
Resources/costs	Number of mammograms, unnecessary biopsies
Time horizon	Remaining lifetime of women

AHRQ, Agency for Healthcare Research and Quality; HRT, hormone replacement therapy; NCI, National Cancer Institute.