Risk of bias of included studies
| Author, year(country) | Sequence generation | Allocation concealment | Blinding of participants and personnel | Blinding of outcome assessment | Incomplete outcome data | Selective outcome reporting | Other | Overall RoB |
|---|---|---|---|---|---|---|---|---|
| Booth, 2008 (Australia) | Unclear | Unclear | Unclear | Low | High | Low | Low | High |
| Brindal, 2012 (Australia) | Low | Low | Low | Low | High | Low | Low | High |
| Carr, 2013 (USA) | Low | Low | High | Low | Low | Low | High | High |
| Cavallo, 2012 (USA) | Unclear | Unclear | Unclear | Unclear | Low | Low | Low | Unclear |
| Celio, 2005 (USA) | Unclear | Low | High | Unclear | Low | Low | Low | High |
| DeBar, 2009 (USA) | Low | Low | High | Low | Low | Low | Low | High |
| Ferney, 2009 (Australia) | Low | Unclear | Unclear | Unclear | Low | Low | Unclear | Unclear |
| van Genugten, 2012 (Netherlands) | Low | Unclear | Unclear | Unclear | High | Low | Low | High |
| Gold, 2007 (USA) | Unclear | Unclear | Unclear | Unclear | High | Low | Low | High |
| Gow, 2010 (USA) | Low | Unclear | High | Low | Low | Low | High | High |
| Harvey-Berino, 2004 (USA) | Unclear | Unclear | Unclear | Unclear | High | Low | Low | High |
| Hurling, 2007 (UK) | Unclear | Unclear | Unclear | Low | Unclear | Low | Low | Unclear |
| Lao, 2011 (USA) | Unclear | Unclear | High | High | High | Low | High | High |
| Micco, 2007 (USA) | Unclear | Unclear | Unclear | Unclear | Unclear | Low | High | High |
| Morgan, 2011 (Australia) | Low | Low | Unclear | Low | High | Low | Low | High |
| Pullen, 2008 (USA) | Unclear | Unclear | Unclear | Unclear | High | Low | Unclear | High |
| Rydell, 2005 (USA) | Unclear | Unclear | Unclear | Low | Low | Low | Low | Unclear |
| Spittaels, 2007 (Belgium) | Unclear | Unclear | Unclear | Unclear | Low | Low | High | High |
| Tate, 2001 (USA) | Unclear | Unclear | Unclear | Unclear | High | Low | Low | High |
| Tate, 2006 (USA) | Low | Unclear | Unclear | Unclear | Low | Low | High | High |
| Webber, 2010 (USA) | Unclear | Unclear | Unclear | Low | Low | Low | Low | Unclear |
| Womble, 2004 (USA) | Unclear | Unclear | Unclear | Unclear | High | Low | Low | High |