Fig. 5From: Item response theory and differential test functioning analysis of the HBSC-Symptom-Checklist across 46 countriesItem parameter for the unidimensional GRM after alignment (Items 1–4). Notes. Item discrimination and threshold parameters with 95% CI. Vertical lines represent weighted average across all groups. Items (1) headache, (2) stomachache, (3) backache, (4) feeling low. The abbreviations of the country names can be found in Table 1Back to article page