Fig. 5From: Validation and psychometric properties of the Somatic and Psychological HEalth REport (SPHERE) in a young Australian-based population sample using non-parametric item response theoryResponse Step Functions of the 14 items proposed to measure anxiety-depression. For each item, two IRSF are calculated that correspond to the probability of having the symptom more than often (dark blue line) and the probability of having the symptom most of the time (light blue line). Dotted lines correspond to the 95% confidence interval of the IRSF. Using NIRT estimation, we do not constrain the IRSF to be logisticBack to article page