Table 2.

Assessments of heterogeneity and publication bias for studies on attack rates of mass hysteria in children and adolescents.

Subgroups	Sample size	Number of studies	Heterogeneity		Begg test	Egger test
			I2 (%)	p-value	Z value (p-value)	t value (p-value)
Gender
Girl	11,977	9	95.0	<0.001	−1.64 (0.152)	−1.95 (0.099)
Boy	8,723	9	96.0	<0.001	−0.61 (0.453)	−0.36 (0.452)
Education level
Entire school	10,861	2	99.0	<0.010	1.24 (0.115)	1.88 (0.067)
High school	6,278	4	98.0	<0.010	0.58 (0.464)	0.35 (0.789)
Middle school	8,205	9	98.0	<0.010	−1.91 (0.202)	−2.55 (0.037)
Primary school	7,543	13	99.0	<0.001	0.89 (0.251)	−3.05 (0.011)
Area
Rural	21,100	22	99.0	<0.001	−1.95 (0.051)	1.99 (0.048)
Urban	11,787	6	98.0	<0.010	0.89 (0.224)	2.64 (0.035)
Trigger factors
Mass vaccination	12,248	6	99.0	<0.001	−0.74 (0.112)	2.19 (0.022)
Psychological suggestion	2,091	3	97.0	<0.010	−1.26 (0.127)	1.98 (0.046)
Supernaturalism	6,362	4	99.0	<0.010	0.89 (0.184)	2.57 (0.031)
Suspected food poisoning	6,173	7	99.0	<0.001	1.98 (0.088)	1.75 (0.109)
Water pollution	1,955	2	91.0	<0.001	2.11 (0.077)	2.77 (0.023)
Study pressure	1,592	2	43.0	0.020	0.85 (0.144)	−1.03 (0.104)
Location of occurrence
China	23,342	21	99.0	0.001	−2.85 (0.041)	2.63 (0.026)
Outside China	9,545	7	97.0	<0.010	1.04 (0.235)	0.89 (0.364)
Publication year
2010–2014	27,741	22	99.0	<0.001	0.94 (0.207)	1.59 (0.126)
2015–2020	5,146	6	96.0	<0.010	−0.77 (0.164)	1.87 (0.061)
Student type
Resident	20,781	12	99.0	<0.010	1.74 (0.091)	1.02 (0.303)
Nonresident	12,106	16	99.0	<0.001	1.49 (0.094)	−2.87 (0.025)