This panel presentation and discussion will consider the possibilities for using large existing data sets such as repositories of health care insurance claims and encounter data and national surveys such as the Medical Expenditure Panel Survey to assess the overall impact of the Affordable Care Act (ACA) on access, outcomes, and costs of health care. Repositories of claims and encounter data may include commercially available data sources such as IMS Pharmetrics(R) or Truven Market Scan(R) and government sources such as the Medicaid Statistical Information System (MSIS). The presentation and discussion will include the logical framework (application of logic models), study design issues and options, data sources and availability, analytic techniques, key evaluation questions, and study limitations, validity threats, and caveats. #HealthEvaluation #AffordableCareAct #2013Conference