. 2021 Nov 15;93(2):e168–e187. doi: 10.1111/cdev.13712

TABLE 1.

Descriptive statistics and correlations of the study variables (n = 1419)

		T	M/%	SD	Min.	Max.	1	2	3	4	5	6	7
		T	M/%	SD	Min.	Max.	r	r	r	r	r	r	r
1	Problematic SMU	1	1.129	1.494	0	8
		2	1.293	1.616	0	9
		3	1.152	1.464	0	9
		4	1.065	1.431	0	9
2	SMU frequency	1	3.923	1.586	1.000	7.000	.341^***
		2	4.271	1.565	1.000	7.000	.317^***
		3	4.285	1.485	1.000	7.000	.243^***
		4	4.296	1.376	1.000	7.000	.251^***
3	Life satisfaction	1	4.932	0.757	1.143	6.000	−.282^***	−.098^**
		2	4.687	0.874	1.000	6.000	−.310^***	−.089^**
		3	4.540	0.876	1.000	6.000	−.306^***	−.044
		4	4.476	0.884	1.000	6.000	−.241^***	−.028
4	Self‐esteem	1	3.946	0.685	1.200	5.000	−.198^***	−.066	.516^***
		2	3.865	0.758	1.000	5.000	−.270^***	−.109^***	.628^***
		3	3.757	0.738	1.000	5.000	−.297^***	−.052	.628^***
		4	3.730	0.745	1.000	5.000	−.180^***	−.032	.593^***
5	Attention deficits	1	2.115	0.703	1.000	4.333	.349^***	.193^***	−.318^***	−.191^***
		2	2.266	0.773	1.000	5.000	.379^***	.236^***	−.287^***	−.246^***
		3	2.399	0.754	1.000	5.000	.312^***	.150^***	−.257^***	−.254^***
		4	2.463	0.783	1.000	5.000	.267^***	.108^**	−.199^***	−.214^***
6	Impulsivity	1	1.863	0.682	1.000	4.667	.357^***	.276^***	−.170^***	−.081^**	.656^***
		2	1.926	0.745	1.000	5.000	.357^***	.264^***	−.201^***	−.167^***	.683^***
		3	1.947	0.678	1.000	5.000	.308^***	.200^***	−.178^***	−.168^***	.624^***
		4	1.934	0.650	1.000	4.000	.241^***	.172^***	−.085^*	−.134^***	.642^***
7	Social competence	1	4.401	0.628	1.800	5.000	−.197^***	.067	.285^***	.291^***	−.156^***	−.146^***
		2	4.354	0.681	1.200	5.000	−.108^***	.117^***	.208^***	.253^***	−.148^***	−.166^***
		3	4.322	0.700	1.000	5.000	−.127^***	.098^**	.303^***	.360^***	−.185^***	−.214^***
		4	4.352	0.675	1.200	5.000	−.137^**	.211^***	.275^***	.308^***	−.115^**	−.060
8	Female	1–4	45.9		0	1	−.060	.163^***	−.102^*	−.169^***	−.150^**	−.265^***	.161^**
							.079^*	.276^***	−.112^**	−.148^***	−.022	−.164^***	.231^***
							.084^*	.213^***	−.032	−.088^*	−.073	−.177^***	.208^***
							.066	.196^***	−.053	−.047	−.068	−.117^*	.283^***
9	Pre‐vocational education	1–4	57.8		0	1	.322^***	.237^***	−.082	−.015	.135^**	.221^***	−.097
							.150^***	.171^***	.010	−.064	.052	.190^***	−.035
							.104^**	.164^***	.012	−.010	−.026	.076^*	−.035
							.094^*	.099^**	−.011	−.096^*	−.117^**	−.011	−.103^**
10	Immigrant background	1–4	21.8		0	1	.076	.046	−.022	−.043	−.077	−.005	.028
							.041	−.024	.102^*	.099^**	−.106^**	−.015	.002
							.017	−.034	<.001	.075	−.066	.048	−.075
							−.019	−.087	−.159^*	<.001	−.040	−.064	−.252^***

Means and standard deviations are based on complete data.

Abbreviations: M, mean; Max., maximum; Min., minimum; r, pairwise correlation; SD, standard deviation; SMU, social media use; T, timepoint (i.e., wave).

p < .05

^**

p < .01

^***

p < .001.