Evaluation of Buss-Perry aggression Questionnaire with item response theory (IRT)

The aim of this research was to examine the psychometric properties of the Buss-Perry Aggression Questionnaire on Serbian sample, using the IRT model for graded responses. AQ contains four subscales: Physical aggression, Verbal aggression, Hostility and Anger. The sample included 1272 participants, both gender and age ranged from 18 to 68 years, with average age of 31.39 (SD = 12.63) years. Results of IRT analysis suggested that the subscales had greater information in the range of above-average scores, namely in participants with higher level of aggressiveness. The exception was Hostilisty subscale, because it was informative in the wider range of trait. On the other hand, this subscale contains two items which violate assumption of homogenity. Implications for measurement of aggressiveness are discussed.