Test information function for the MSK-HQ

Test information (y-axis) relates to the precision of the scale (i.e. reliability) given the level of latent musculoskeletal health variable (x-axis). Dashed lines indicate levels of information where reliability on the familiar metric (e.g. that of Chronbach’s α) is 0.8 and 0.9. Reliability is high from around three standard deviations below to three standard deviations above the mean of the latent musculoskeletal health variable. MSK-HQ: Musculoskeletal Health Questionnaire.