| Study | Allocation generation | Allocated concealment | Implementation bias | Measurement bias | Follow-up bias | Report bias | Other bias |
| Williams et al. (2002) | Unclear | Unclear | Unclear | Unclear | High | High | High |
| McNeely et al. (2004) | Computer-generated | High | Assessor blinded | High | High | High | High |
| Gradalski et al. (2015) | Unclear | Unclear | Assessor blinded | High | High | High | High |
| Tambour et al. (2018) | Unclear | Unclear | Assessor blinded | High | High | High | High |
| Andersen et al. (2000) | Unclear | Unclear | Unclear | High | High | High | High |
| Dayes et al. (2013) | Computer-generated | High | Assessor blinded | High | High | High | High |