An official website of the United States government
Here's how you know
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.
Scatter plot of ratio of odds ratios with (a) impact factor in case-control studies, (b) log(number of cases) in case-control studies, (c) impact factor in cohort studies, and (d) log(number of cases) in cohort studies.