Sample size
With respect to the baseline survey, we will implement a convenience sampling procedure: That means that all facilities taking part in one of the three patient registries have been informed about the ongoing KICK-COVID study via newsletters and regular meetings of the collaborators. We aim to include (and re-assess) as many participants as possible in order to get sufficient data sets to make generalizable statements. Therefore, we intend to recruit at least 1000 parents of either children or adolescents per CC. In addition, we assume that around 500 adolescents (> 12 yrs) per CC will fill in the baseline survey. For the web-based psychosocial assessment, the primary goal is to get a deeper understanding of the assumed psychosocial processes that can explain the level of mental and physical strain experienced. Therefore, we aim to include a subsample of participants of the baseline survey. To apply structural equation modeling (SEM) required sample sizes are dependent on various data characteristics such as data distribution, the number of missing data, or parameters that have to be computed. According to Kline [