This document has been superseded.
This report is part of the RAND Corporation perspective series. RAND perspectives present informed perspective on a timely topic that address the challenges facing the public and private sectors. All RAND perspectives undergo rigorous peer review to ensure high standards for research quality and objectivity.
The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.