Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Map of studies and concepts included and excluded, measured by number of studies included in each concept (studies were identified via a computerized search and handsearching gray literature/reference lists). Concepts depicted in gray were excluded following phase three of screening.
