Item Response Theory-based validation of a short form of the Disordered Eating Attitude Scale (DEAS-s) to a Brazilian sample

Abstract

This study aimed to validate a short version of the Disordered Eating Attitude Scale (DEAS-s). To this end, 2,902 adult individuals answered the original DEAS and informed age, weight, and height. Data were analyzed using the full-information factor analysis and Item Response Theory (IRT) analysis. Exclusion criteria retained items with adequate values of commonality and factor loadings. Estimation of IRT parameters, the Item Characteristic Curve (ICC), and test information guided the selection of the best quality items. The final model adjustment was evaluated using Root Mean Square Error of Approximation (RMSEA), Standardized Root Mean Square Residual (SRMSR), Comparative Fit Index (CFI), and Tucker-Lewis Index (TLI). The eating attitudes on each level of DEAS-s were described. The analyses were performed on R software and Microsoft Excel version 2013. As results, six items were excluded because of the low communalities and factor loadings, and one more was excluded because of an overlapping on the ICC. The remaining 17 items explained 0.53 of the total variance and had an adequate goodness-of-fit (RMSEA = 0.05; SRMSR = 0.05; CFI = 0.98; TLI = 0.98). The information test is more accurate between the scores 0 and +3. Scores higher or equal to 1.5 identified individuals with disordered eating attitudes. Women, older individuals, and those with a higher body mass index presented more disordered eating; thus, the one-dimensional and short version of DEAS showed a suitable adjustment and may contribute to properly evaluate disordered eating in diverse populations.