To identify a possible clustering effect of data in schools, the intraclass correlation coefficient (ICCLogit) for a generalized linear mixed model with binary outcome was calculated according to Eldridge et al. . Depending on the magnitude of the ICCLogit, the appropriate regression analysis, a logistic or a generalized linear mixed model, was conducted subsequently, considering the variables described above. A closer examination of decisive factors for target groups and target behaviors was realized in two sub-models. These analyses were performed with the statistical software R Release 3.2.5 for Windows (http://cran.r-project.org/).