RT Book, Section A1 Dimick, Justin B. A1 Ryan, Andrew M. A2 Livingston, Edward H. A2 Lewis, Roger J. SR Print(0) ID 1184194809 T1 Methods for Evaluating Changes in Health Care Policy—The Difference-in-Differences Approach T2 JAMA Guide to Statistics and Methods YR 2019 FD 2019 PB McGraw-Hill Education PP New York, NY SN 9781260455328 LK jamaevidence.mhmedical.com/content.aspx?aid=1184194809 RD 2024/03/29 AB This JAMA Guide to Statistics and Methods describes when to use a difference-in-differences analysis to evaluate changes in health care before and after changes in health care policy.