ITQ subscales: SPSS syntax for score conversion and DIF-equating after Rasch analysis

The SPSS syntax provides is concerned with conversions of the scores from the International Trauma Questionnare (ITQ) following ietm analysis by Rasch measurement models. More specifically, it provides: 1) Conversion of post-traumatic stress disorder (PTSD) raw scores to weighted maximum likelihood estimates of person parameter estimates adjusted for DIF as well as DIF-equating of the raw score for differential item functioning (DIF) relative to gender and time since trauma. 2) Conversion of disturbances in self-organisation (DSO) raw scores to weighted maximum likelihood estimates of person parameter estimates. The syntax is based on results reported in Tables 6 and 7 in: Nielsen, T., Elklit, A., Vang, M. L., Brødsgaard Nielsen, S. Auning-Hansen, M. & Palic, A. (2023). Cross-cultural validity and psychometric properties of the International Trauma Questionnaire (ITQ) in a clinical refugee sample. European Journal of Psychotraumatology. https://doi.org/10.1080/20008066.2023.2172256