Sonja Mensch

60 Chapter 3 Table 1. Cosmin Box D content validity (Mokkink et al., 2012) General requirements Yes No ? 1 Was there an assessment of whether all items refer to relevant aspects of the construct to be measured? ☐ ☐ ☐ 2 Was there an assessment of whether all items are relevant for the study population? (e.g. age, gender, disease characteristics, country, setting) ☐ ☐ ☐ 3 Was there an assessment of whether all items are relevant for the purpose of the measurement instrument? (discriminative, evaluative, and/or predictive) ☐ ☐ ☐ 4 Was there an assessment of whether all items together comprehensively reflect the construct to be measured? ☐ ☐ ☐ 5 Were there any important flaws in the design or methods of the study? ☐ ☐ ☐ Step 1: Listing of relevant motor abilities. To identify motor abilities that are most relevant to children with SMD, we listed common treatment goals formulated in clinical practice using a survey. Twenty-five physical therapists, working with clients with SMD at a care provider service, were asked to collect all therapeutic long-term and short-term goals from their client files, formulated during the last five years. Step 2: Structure and layout of the instrument. As mentioned before, the five formulated suitability criteria as shown in appendix A, were the starting point for constructing the new instrument. Furthermore, the structure of the newly designed instrument was partially based on that of other instruments (e.g. start with the main positions of lying, sitting and standing) taking into account the relevance of specific situations and activities. These situations and activities were selected in concordance with collected therapeutic goals from the first step using the collective experience of the expert focus group. For the development of the structure and layout of the instrument, the expert focus group followed a repeated consensus procedure. Step 3: Pilot study on applicability Physical therapists working with children and adults with SMD from different care- organisations in the Netherlands were asked to participate in a pilot study. In total, twenty-six physical therapists evaluated the instrument’s applicability and whether test items met the criteria for good content validity. None of these physical therapists were members of the expert focus group. They received a four-hour training on the web based computer application used to complete all items and on the user manual.