Table 4.

Results of moderating effects of different moderating variables.

Adjustment variables	Type	Number of effects	Effect value	Degree of influence	95% confidence interval		Two-tailed test
					Lower limit	Upper limit	Z-value	P-value
Country Region	North Africa	1	2.033	Larger	0.190	0.857	1.249	0.212
	North America	14	0.061	Smaller	1.447	2.618	6.806	0.000
	Oceania	9	0.334	Middle	0.058	0.258	1.239	0.215
	Southeast Asia	15	0.684	Middle	0.019	0.184	1.586	0.113
	Eastern Europe	1	0.305	Middle	0.382	0.665	7.229	0.000
	East Asia	94	0.550	Middle	0.509	0.710	11.850	0.000
	South America	1	1.145	Larger	0.190	0.857	1.249	0.212
	Western Europe	32	0.076	Smaller	1.447	2.618	6.806	0.000
	Western Asia	23	0.594	Middle	0.058	0.258	1.239	0.215
	Combined effect volume	190	0.358	Middle	0.303	0.420	12.073	0.000
Learning period	Primary School	41	0.527	Middle	0.369	0.684	6.541	0.000
	Junior High School	52	0.520	Middle	0.388	0.651	7.754	0.000
	High School	40	0.720	Middle	0.558	0.881	8.727	0.000
	University	57	0.116	Smaller	0.027	0.204	2.550	0.011
	Combined effect volume	190	0.355	Middle	0.294	0.417	11.293	0.000
Group size*	3 and below	2	0.778	Middle	0.464	1.093	4.852	0.000
	4–5	23	0.909	Larger	0.720	1.099	9.428	0.000
	6–7	42	0.436	Middle	0.310	0.562	6.764	0.000
	8 and above	14	0.514	Middle	0.229	0.799	3.538	0.000
	Combined effect volume	81	0.592	Middle	0.498	0.686	12.344	0.000
Class size	small	104	0.483	Middle	0.387	0.578	9.936	0.000
	Middle	71	0.466	Middle	0.338	0.594	7.124	0.000
	Big	15	0.106	Smaller	0.021	0.233	1.642	0.101
	Combined effect volume	190	0.378	Middle	0.313	0.444	11.319	0.000
Subject category	Engineering and technology	62	0.619	Middle	0.482	0.756	8.844	0.000
	Humanities and Society	55	0.284	Middle	0.166	0.402	4.720	0.000
	Life science	3	0.708	Middle	0.482	0.933	6.147	0.000
	Natural science	42	0.484	Middle	0.365	0.602	7.997	0.000
	Other	28	0.275	Middle	0.107	0.442	3.214	0.001
	Combined effect volume	190	0.443	Middle	0.380	0.506	13.773	0.000
Course type	Theory class	103	0.393	Middle	0.297	0.488	8.088	0.000
	Experimental class	87	0.498	Middle	0.395	0.600	9.541	0.000
	Combined effect volume	190	0.441	Middle	0.372	0.511	12.420	0.000
Experimental period	Single experiment	28	0.359	Middle	0.241	0.478	5.947	0.000
	1–8 weeks	62	0.498	Middle	0.380	0.615	8.321	0.000
	9–18 weeks	35	0.673	Middle	0.494	0.853	7.353	0.000
	18 weeks or more	65	0.300	Middle	0.179	0.420	4.874	0.000
	Combined effect volume	190	0.424	Middle	0.360	0.488	12.972	0.000

^*To avoid the inclusion of literature that did not provide group size numbers from influencing the study results, only literature that did provide data was included in the analysis here.

Other literature included in the meta-analysis (Beier et al., 2019; Castro-Vargas et al., 2020; Chung, 2021; Ergül and Kargın, 2014; Hugerat, 2016; Hung et al., 2012; Lazić et al., 2021; Lin and Lu, 2018; Mark, 2022; Ozdamli and Turan, 2017; Ruiz-Rosa et al. (2013; Wang et al., 2016; Wurdinger and Qureshi, 2015; Zulaeha et al., 2020.).