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.
Total and percentage of qualifying PEM articles published 2004–2008 and 2009–2013 stratified by study design
| 2004–2008 | 2009–2013 | |||
|---|---|---|---|---|
| Study Design | Total | % of all qualifying PEM articles |
Total | % of all qualifying PEM articles |
| Randomized controlled trial | 111 | 55.0 | 107 | 40.8 |
| ProspectiveNon-Interventional | 56 | 27.7 | 83 | 31.7 |
| Retrospective | 19 | 9.4 | 47 | 17.9 |
| Study Specific Methods | 16 | 7.9 | 25 | 9.5 |
Chi-square test p-value=0.0089
