Multidimensional item Response theory to assess the psychometric properties of persian version of dutch eating behavior questionnaire (DEBQ) in university students

The Multidimensional item response theory (MIRT) is a powerful modeling approach which could provide an ideal foundation for health psychologists to improve their survey-development and assessment. The current study aimed to illustrate the advantages of applying the MIRT models in investigating psychometric quality of the Dutch Eating Behavior Questionnaire (DEBQ). The Persian version of DEBQ questionnaire was administered to a sample of 509 Iranian university students. The three-factor MIRT model was applied to model the observed scores for each item of the DEBQ as a probability function of the individual's latent traits (here eating behaviors) while taking the correlation among questionnaire's dimensions into account. Strength of fit of MIRT model was reported based on multiple indices and individual items were illustrate in detail through item characteristic curves. Item information curves were also described the amount of information carried by different items. The goodness of fit indices which extracted from the result of MIRT model indicated acceptable structural validity of DEBQ with three factor to support for the dominant three-dimensional structure. Item discrimination parameters ranged from 0.56 to 3.39, 0.77 to 3.56 and 0.67 to 2.14 for restrained eating, emotional eating, and external eating, respectively. Moreover, items 4, item 23 and item 30 provided the least information in restrained, emotional, and external eating subscales.