Maartje Boer

CHAPTER 2 50 Table 2.5 Zero-Inflated Negative Binomial and Multinomial Regression, Demographic Characteristics and Problematic SMU, n = 6,626 Zero-inflated negative binomial Multinomial (ref. = normative SMU, max. 1 criterion) Number of endorsed criteria Risky SMU (2 to 5 criteria) Problematic SMU (6 to 9 criteria) B SE IRR B SE OR M% B SE OR M% Gender Boys ref. ref. 28.86 ref. 2.89 Girls 0.25*** 0.03 1.28 0.58*** 0.06 1.79 41.29 0.56*** 0.14 1.75 4.06 Educational level High (pre-university) ref. (a) ref. (a) 30.57 ref. (a) 1.81 Medium (general higher) 0.24*** (b) 0.04 1.27 0.30** (b) 0.08 1.36 36.61 0.82** (b) 0.23 2.27 3.63 Low (pre-vocational) 0.35*** (c) 0.04 1.42 0.31** (b) 0.08 1.36 36.18 1.14*** (b) 0.22 3.14 4.95 Age 12 ref. (a) ref. (a) 30.81 ref. (a) 2.55 13 0.14 (ab) 0.05 1.15 0.29* (b) 0.09 1.34 36.98 0.36 (a) 0.22 1.43 3.27 14 0.14 (ab) 0.05 1.16 0.25 (ab) 0.09 1.29 35.74 0.61 (a) 0.23 1.84 4.23 15 0.15* (b) 0.05 1.16 0.29* (b) 0.09 1.34 36.67 0.55 (a) 0.22 1.73 3.93 16 0.05 (ab) 0.05 1.05 0.12 (ab) 0.10 1.12 33.04 0.33 (a) 0.23 1.40 3.40 Ethnic background Native ref. (a) ref. (a) 34.19 ref. (a) 3.10 Non-Western 0.19* (b) 0.04 1.20 0.14 (a) 0.08 1.15 36.63 0.56** (b) 0.17 1.75 5.05 Other Western 0.14 (ab) 0.06 1.15 0.16 (a) 0.12 1.17 36.92 0.60 (ab) 0.29 1.82 5.20 Notes. SMU = social media use; SE = standard error; IRR incidence rate ratio; OR = odds ratio; M% = margin, i.e. expected probability while holding all covariates at their means; Ref. = reference category. Rows with different letters denote significant group differences at p < 0.05 with Bonferroni correction. * p < 0.05, ** p < 0.01, *** p < 0.001.