Validity Study of the Beck Anxiety Inventory (Portuguese version) by the Rasch Rating Scale Model

Our objective was to conduct a validation study of the Portuguese version of the Beck Anxiety Inventory (BAI) by means of the Rasch Rating Scale Model, and then compare it with the most used scales of anxiety in Portugal. The sample consisted of 1,160 adults (427 men and 733 women), aged 18-82 years old (M=33.39; SD=11.85). Instruments were Beck Anxiety Inventory, State-Trait Anxiety Inventory and Zung Self-Rating Anxiety Scale. It was found that Beck Anxiety Inventory's system of four categories, the data-model fit, and people reliability were adequate. The measure can be considered as unidimensional. Gender and age-related differences were not a threat to the validity. BAI correlated significantly with other anxiety measures. In conclusion, BAI shows good psychometric quality.