Construct validity and reliability of Olweus Bully/Victim Questionnaire – Brazilian version

The Revised Olweus Bully/Victim Questionnaire (OBVQ) is among the few bullying assessment instruments with well-established psychometric properties in different countries. Nevertheless, the psychometric properties of the Brazilian version (Questionário de Bullying de Olweus - QBO) have not been determined. We aimed at verifying the construct validity and reliability of the bully and victim scales of the QBO. To achieve that goal, the victim and bully scales were assessed using polytomous item response theory (IRT). The best fit was obtained with a generalized partial credit model that is capable of measuring the specific discriminating power for each item in these scales. The QBO was administered to 703 public school students (mean age: 13 years; standard deviation = 1.58). Based on IRT analysis, the number of response categories in each item was reduced from four to three. Cronbach reliability scores were satisfactory: α = 0.85 (victim scale) and α = 0.87 (bully scale). In this study, hurtful comments, persecution, or threats had high power to discriminate victims and bullies. For both QBO scales, higher severity parameters were observed for direct bullying items. The results also show that the construct of both QBO scales measures the same construct proposed for the overall instrument. Thus, the QBO can be administered to different Brazilian populations to assess the main characteristics of bullying: repetition of behavior over time and intentionally acting to humiliate, threaten, or harm somebody.