Table 2.

Risk of Bias analysis. To obtain the percentage score, the total score was divided by 28 (= 14*2) and multiplied by 100.

Author	Q1	Q2	Q3	Q4	Q5	Q6	Q7	Q8	Q9	Q10	Q11	Q12	Q13	Q14	Total	Percentage (%)
Al-Shargie et al. (2016)	2	2	0	2	2	2	1	2	0	1	0	2	1	1	18	64
Al-Shargie (2017a, 2017b)	2	2	0	2	2	2	1	2	0	1	1	2	2	2	21	75
Al-Shargie (2017a, 2017b)	2	2	0	2	2	2	1	1	0	1	0	1	2	2	18	64
Al-Shargie (2017a, 2017b)	2	2	0	1	2	2	1	2	0	1	2	1	1	1	18	64
Betti et al. (2018)	2	2	2	2	2	2	1	1	0	0	2	1	2	1	20	71
Brouwer et al. (2011)	2	1	1	1	2	2	2	2	0	1	1	1	2	1	19	68
Crost et al. (2008)	2	1	1	1	1	2	1	2	2	1	1	1	2	2	20	71
Düsing et al. (2016)	2	2	2	2	2	2	1	2	1	2	2	1	2	2	25	89
Ehrhardt et al. (2021)	2	2	0	2	2	2	1	2	1	1	2	1	2	2	22	79
Guo et al. (2019)	2	2	1	2	2	2	1	1	2	1	2	1	1	2	22	79
Hafeez et al. (2018)	2	2	1	1	2	2	1	2	0	1	1	1	2	1	19	68
Hofmann et al. (2005)	2	2	2	2	2	2	2	2	0	1	1	1	2	2	23	82
Hofmann (2006)	2	2	2	2	2	2	1	1	0	1	1	1	2	2	21	75
Izhar et al. (2019)	2	2	1	2	2	2	1	2	0	1	2	1	2	2	22	79
Kawamoto et al. (2013)	2	2	0	1	2	2	0	2	0	1	1	1	2	2	18	64
Kortink et al. (2018)	2	2	1	2	2	2	2	2	1	1	0	1	2	2	22	79
Minguillon et al. (2016)	2	2	0	1	2	2	1	1	0	1	0	1	2	2	17	61
Minguillon et al. (2017)	2	2	1	1	2	2	1	1	0	1	0	1	2	2	18	64
Papousek et al. (2019)	2	2	1	2	2	2	2	2	2	1	0	2	2	2	24	86
Pérez-Edgar et al. (2013)	2	2	2	2	2	2	1	1	1	1	2	1	2	2	23	82
Perrin et al. (2019)	2	1	1	2	2	2	2	1	0	1	2	1	1	2	20	71
Peterson et al. (2011)	2	2	2	1	2	2	2	1	0	1	2	1	2	2	22	79
Poppelaars et al. (2018)	2	2	2	2	2	2	2	2	2	1	2	1	2	2	26	93
Poppelaars et al. (2021)	2	2	1	2	2	2	1	2	2	1	2	1	2	2	24	86
Quaedflieg et al. (2015)	2	2	1	2	2	2	2	2	2	1	2	1	2	2	25	89
Subhani et al. (2013)	2	2	0	1	2	2	1	2	0	1	2	1	1	2	19	68
Subhani et al. (2016)a	2	2	0	0	2	2	1	2	0	1	0	1	2	1	16	57
Subhani et al. (2016)b	2	2	1	1	2	2	1	2	0	1	0	1	1	1	17	61
van der Veen et al. (2016)	2	2	1	2	2	2	1	2	2	1	1	1	2	2	23	82
Vaquero-Blasco et al. (2020)	2	2	0	1	2	2	1	2	0	1	0	1	2	2	18	64
Vaquero-Blasco et al. (2021)	2	2	1	2	2	2	1	1	0	1	0	1	1	2	18	64
Verona et al. (2009)	2	2	1	2	2	2	2	2	1	1	2	1	2	2	24	86
Wang et al. (2015)	2	2	2	2	2	2	1	2	2	1	2	1	2	2	25	89
Yao et al. (2020)	2	2	0	2	2	2	2	2	2	1	0	1	2	2	22	79

^a= Subhani, A. R., Malik, A. S., Kamil, N., & Saad, M. N. M.

^bSubhani, A. R., Malik, A. S., Kamil, N., Naufal, M., & Saad, M. N. M.