Table 2

Summary scores^* of studies based on different QATs

ID	Author(s) (year)	Study design	EPHPPT	CASP	NOS	Liverpool	GATE	ROB
1a	Birmingham et al (1997)	Case-control study	−0.40	0.44	−0.11	−0.42	−0.39	−0.56
1b	Birmingham et al (1997)	Case-control study	−0.40	0.33	0.11	−0.38	−0.33	−0.56
2	Han and Hlaing (1989)	RCT	0.50	0.88	NA	0.50	0.24	−0.33
3	Hoque et al (1999)	Case-control study	0.40	0.56	0.33	0.50	0.39	−0.22
4	Hussein Gasem et al (2001)	Case-control study	0.40	0.89	0.11	0.00	0.17	−0.22
5	Khan (1982)	Non-randomised trial	−0.83	NA	NA	−0.11	−0.48	−1.00
6	Khin et al (1994)	Case-control study	−0.60	0.00	−0.11	−0.50	−0.61	−0.67
7	Peterson et al (1998)	Cohort study	−0.17	0.50	0.33	−0.67	−0.17	−0.78
8	Shahid et al (1996)	Non-randomised trial	−0.17	NA	NA	−0.33	0.16	−0.44
9	Sircar et al (1987)	Non-randomised trial	−0.67	NA	NA	−0.50	−0.36	−0.89
10	St Louis et al (1990)	Case-control study	−0.40	0.22	−0.11	−0.56	0.11	−0.67
11	Velema et al (1997)	Case-control study	−0.40	0.00	0.11	−0.50	−0.06	−0.44
12	Wilson et al (1991)	Non-randomised trial	−0.67	NA	NA	−0.83	−0.20	−0.89
13	Yeager et al (1991)	Household survey	0.00	NA	NA	−0.44	−0.06	−0.33

↵* Summary scores can range from −1 (low quality) to 0 (moderate quality) and +1 (high quality).
CASP, Critical Appraisal Skills Programme; EPHPPT, Effective Public Health Practice Project tool; GATE, Graphical Appraisal Tool for Epidemiological Studies; NA, not applicable; NOS, Newcastle–Ottawa Scale; QAT, quality appraisal tool; RCT, randomised controlled trial; ROB, Cochrane Collaboration Risk of Bias tool.