Sonja Mensch

88 Chapter 4 in the country so we can assume the study population is representative and adequately reflects the diversity of the target group. It is encouraging that reliability levels were adequate despite this heterogeneity. A lower concordance of inter-rater than of test-retest scores was to be expected, because of the relative small number of participants, but also because of the subjectivity introduced by therapists having to estimate the extent in which they used manual support. Nevertheless, the high ICC’s (Tables 2 and 3) support the strong design of Movakic, including the application of manual support. This study has several strengths. It is one of the few studies in this specific target population with relatively high participation rates e.g. (Veugelers et al., 2005) (Calis et al., 2008) (Veugelers et al., 2010) (Liptak et al., 2001) (Brug ten, Putten van der , Penne, Maes, & Vlaskamp., 2012) (Putten van der, Vlaskamp, Reynders, & Nakken., 2005) (Putten van der & Vlaskamp., 2011) (Calis et al., 2010) (Rieken et al., 2011). Moreover, all participating therapists received adequate training in the use of the instrument related to the purpose of the study. Additionally, all had extensive experience with the target population and were familiar with the included children. The therapists thus fulfilled the prerequisites for participating in the study as raters. Electronic data collection ensured that the data is of good quality and scoring errors were limited. A memory effect was highly minimalized by not showing scores during completion of the questionnaire and the wide time frame of three months. Moreover, therapists noted events that may have influenced the children’s scores during the interval and such intervals were not used for analyses. The time frame of three months may be considered a long period for showing stability of an instrument. However, based on the experience in clinical care of this group of children, it was expected that stability in motor abilities would be high. On the other hand, the high ICC’s may be explained by the extreme familiarity of the therapists with the children, the fact that they all had a long-time experience with the target group, but also by the fact that they were highly motivated because of being personally involved in the development of a new instrument. This situation may be less favorable in future daily practice, where physiotherapists with less experience with these children may have to complete Movakic, who will not always be connected to specialized day-care centers, whose time is not or to a limited extent reimbursed by health insurances, or who work in countries with different healthcare systems. Therefore, training is needed to enhance a correct application of the instrument; even in less favorable circumstances (Mensch et al., 2015b).