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.
Methodological quality scores at various publication times
| Publication date (year grouping) | Studies (n) | Methodological quality score (mean ± SD) | One way analysis of variance p value |
|---|---|---|---|
| 1969–1989 | 38 | 37 ± 15 | 0.04 |
| 1990–1999 | 32 | 45 ± 14 | |
| 2000–2009 | 50 | 43 ± 13 | |
| 2010–2014 | 39 | 46 ± 16 |
SD standard deviation
