Item‐validity analysis of the SED‐S in a multicentre study of adults with intellectual disabilities

Background Valid and reliable instruments for measuring emotional development are critical for a proper diagnostic assignment in individuals with intellectual disabilities. This exploratory study examined the psychometric properties of the items on the Scale of Emotional Development—Short (SED‐S). Method The sample included 612 adults with intellectual disabilities (Mage = 37.35, SDage = 13.27; 59.8% males). Item validity analysis comprising sensitivity and specificity rates and discriminatory power were determined. Results The relative mean frequency of ‘yes’ answers to all 200 items was 29.5%. The mean sensitivity rate was 67.5% and the mean specificity rate was 79.3%. Most items (85.0%) showed good discriminatory power with the adjacent stage(s), especially between SED‐1, SED‐2, SED‐3 and SED‐4. Particularly in SED‐4 some items showed weaknesses in the differentiation between these stages. Discussion This study adds to previous validation studies by showing that most SED‐S items have psychometrically sound properties.