Maartje Boer

SMU AND ADHD-SYMPTOMS 141 5 Table 5.3 Preliminary Results, Standardized (n = 1,629) SMU intensity SMU problems Attention deficits Impulsivity Hyperactivity β SE p β SE p β SE p β SE p β SE p Wave 2 1 0.39 0.06 < 0.001 0.84 0.05 < 0.001 0.27 0.06 < 0.001 -0.05 0.07 0.476 0.09 0.06 0.117 Wave 3 1 0.84 0.06 < 0.001 0.35 0.06 < 0.001 0.67 0.07 < 0.001 0.20 0.06 0.001 0.09 0.07 0.163 Girls 2 0.42 0.09 < 0.001 0.22 0.08 0.007 -0.07 0.09 0.445 -0.18 0.09 0.046 -0.02 0.09 0.842 Prevocational education 3 0.26 0.09 0.003 0.45 0.09 < 0.001 0.25 0.10 0.010 0.28 0.09 0.003 0.26 0.10 0.007 Native ethnic background 4 0.25 0.12 0.034 -0.03 0.012 0.831 0.19 0.13 0.150 0.02 0.14 0.871 0.26 0.11 0.021 ICC 5 0.803 0.899 0.715 0.771 0.756 Notes. SMU = social media use; β = standardized coefficient; SE = standard error; p = p-value; ICC = intraclass correlation. Results represent multilevel multiple regression results estimated with Maximum Likelihood with Robust standard errors (MLR). Observations ( n = 1,629) were nested in individuals ( n = 543). Waves were specified on the within-person level; girls, educational level, and ethnic background were specified on the between-person level. All independent covariates are binary, and therefore all coefficients were standardized based on STD Y -standardization. 1 Reference category = wave 1. 2 Reference category = boys. 3 Reference category = intermediate/pre-university education. 4 Reference category = immigrant background. 5 ICC = variance between / (variance within + variance between).