Table 1 Quality of included studies
References | Randomization method | Blind method | Allocation concealment | Withdrawals/dropouts (NG/NJ) | Jadad score |
|---|---|---|---|---|---|
Clifton et al. (1993) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Shiozaki et al. (1993) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Marion et al. (1997) | Block randomization | Not used | Method not mentioned | Yes | 4 |
Shiozaki et al. (1999) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Jiang et al. (2000) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Shiozaki et al. (2001) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Clifton et al. (2001) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Gal et al. (2002) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Zhi et al. (2003) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Hashiguchi et al. (2003) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Qiu et al. (2005) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Qiu et al. (2006) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Qiu et al. (2007) | Randomization table | Not used | Yes | Yes | 5 |
Lee et al. (2010) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Zhao et al. (2011) | Method not mentioned | Not used | Method not mentioned | Yes | 3 |
Clifton et al. (2011) | Random number generator | Not used | Yes | Yes | 5 |
Andrews et al. (2015) | A central internet or telephone based randomization service | Not used | Yes | Yes | 5 |
Maekawa et al. (2015) | Computer-generated Randomization number | Not used | Method not mentioned | Yes | 4 |