A Tutorial on Systematic Methodology for Psychometric Model Selection: Case Study of the EOAQ-EST

*** Please find the file \"Methodological_EOAQ_Tutorial.pdf\" for detailed instructions *** This tutorial and the accompanying raw data and R scripts support the manuscript entitled \"Improving Measurement in Health Research: Selection of Structural Equation Models Using the European Obesity Academy Questionnaire in Bariatric Patients.\" The tutorial provides a step-by-step approach to construct validation through a systematic methodology for psychometric model selection, using the European Obesity Academy Questionnaire: Expectations of Surgical Treatment (EOAQ-EST) as a case study. The tutorial illustrates the process of identifying the most suitable candidate models from 79 alternatives, based on data from 137 obese female patients. Multigroup confirmatory factor analysis is applied to establish construct validity, reliability and applicability of the psychometric models.