Table 2.
Risk of bias in individual studies
| 1 | 2 | 3 | 4 | 5 | 6 | Global Judgment | |
|---|---|---|---|---|---|---|---|
| Browne 2002 |
yes |
yes |
yes |
yes |
yes |
no |
low |
| deMello 2001 |
unclear |
unclear |
yes |
unclear |
yes |
no |
medium |
| Keller 2000 |
yes |
yes |
yes |
yes |
yes |
yes |
low |
| Kocsis 2009 |
yes |
yes |
yes |
yes |
no |
yes |
low |
| Markowitz 2005 |
yes |
unclear |
yes |
yes |
yes |
yes |
low |
| Miller 1999 |
no |
yes |
unclear |
unclear |
no |
no |
high |
| Ravindran 1999 |
yes |
unclear |
yes |
yes |
no |
yes |
medium |
| Schramm 2008 |
yes |
unclear |
yes |
yes |
yes |
yes |
low |
| Summary “yes” | 6/8 | 4/8 | 7/8 | 6/8 | 5/8 | 5/8 | 4/8 |
1: allocation sequence adequately generated; 2: allocation adequately concealed; 3: knowledge of allocation adequately prevented; 4: incomplete outcome adequately addressed; 5: free of selective outcome reporting; 6: free of other problems.