Table 3.

Downs and Black score for quality assessment.

	Downs and Black Total Score		Crude Agreement	Cohen’s Kappa Coefficient
	Reviewer 1	Reviewer 2
Chen et al. (2011) [14]	13	14	95.8%	0.92
Hou et al. (2015) [15]	16	16	91.7%	0.81
Liporace et al. (2008) [16]	16	15	95.8%	0.91
Singh et al. (2017) [5]	13	16	87.5%	0.74
Zhang et al. (2016) [17]	12	13	95.8%	0.92

Two reviewers (L.E.J. and K.C.-H.) performed quality assessment separately.