Fig. 1

Distribution of the locations of persons (upper panels) and response category thresholds (lower panels) on the common logit metric from less (lower/negative logit locations) to more (higher/positive logit locations) insomnia (x-axis) for the Minimal Insomnia Symptom Scale (MISS; A), the four-item MISS (B), and the MISS-Revised (C). Superimposed green curves represent the information function (IF; higher values = less error and more information, i.e., better measurement precision). Maximum IFs (vertical green lines) correspond to logit locations 0.53 (corresponding raw score, 7; Panel A), 0.77 logit (corresponding raw score, 10; Panel B), and 0.57 (corresponding raw score, 7; Panel C)