The interobserver ICC to the total score was excellent for AMSTAR at 0.84 (95% CI: 0.70, 0.91), and superior to OQAQ, 0.67 (95% CI: 0.38, 0.82). The interrater agreement (kappa) between two assessors for the global assessment (item 10 in OQAQ) was 0.72 (95% CI: 0.48 to 0.85), and better than the self-developed 100-point rating scale: 0.50 (95% CI: 0.07-0.74).