Figure 6.
Control interventions. Number of RCTs classified according to control intervention. Others = control interventions that were used in just 1 RCT.
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.