Table 3.

Study size (N), mean, SD, coefficient of variations (CV), and cluster membership of the included studies.

Study Code	Author, Year	N	Mean	SD	CV	Cluster Membership
P1.01	Chang, 2011 [25]	38	17.50	9.50	54.29	1
P1.04	Nie, 2010 [26]	89	16.70	10.10	60.48	1
P1.05	Pertuz, 2016 [27]	68	16.60	11.20	67.47	1
P1.06	Moon, 2018 [28]	89	20.30	8.60	42.36	1
P1.07	Chen, 2010 [29]	35	16.60	9.30	56.02	1
P1.08	Ha, 2016 [30]	60	15.30	10.07	65.82	1
P4.13	Choi, 2017 [49]	38	14.80	14.40	97.30	1
P4.15	Chan, 2011 [48]	24	21.20	8.30	39.15	1
P6.03	Chen, 2013 [53]	24	20.20	7.80	38.61	1
P1.09	Chen, 2016 [31]	23	24.71	15.16	61.35	2
P1.10	Moon, 2011 [32]	40	23.79	16.62	69.86	2
P1.11	Klifa, 2010 [11]	35	28.00	18.00	64.29	2
P3.01	Bertrand,2015 [36]	182	27.60	20.50	74.28	2
P3.02	Bertrand, 2016 [37]	172	27.40	20.00	72.99	2
P3.03	Dorgan, 2012 [38]	174	28.15	20.39	72.43	2
P4.03	Chen, 2012 [45]	34	24.10	12.40	51.45	2
P6.05	Wengert, 2015 [55]	43	26.05	19.47	74.74	2
P1.12	Chen, 2011 [1]	16	22.10	2.60	11.76	3
P4.14	Chan, 2011 [48]	6	8.70	3.40	39.08	4
P4.16	Chen, 2013 [50]	24	7.50	3.80	50.67	4
P5.04	Tagliafico, 2014 [3]	48	55.00	23.20	42.18	5
P5.08	Ledger, 2016 [54]	10	33.40	16.20	45.76	6