"The Driver Behaviour Questionnaire as a predictor of accidents: A meta-analysis" Comments

A previously published meta-analysis of the predictive power of the Manchester Driver Behaviour Questionnaire (DBQ) versus road traffic crashes is criticized upon a number of counts, including the incomplete handling of common method variance, failure to control for exposure and how the correction for unreliability of the accident variable was undertaken. It is concluded that the results reported, and the conclusions drawn from these, are too favorable to the DBQ, despite the effect sizes being

Common method variance

The main problem associated with the interpretation of the DBQ/accidents association is common method variance (i.e., systematic biases in the self-reports used), which create part or all of the associations found (Chang et al., 2010, Podsakoff et al., 2003). Common method variance may be due to a number of different factors, and in some studies, substantial effects have been found (e.g., Hessing, Elffers, &; Weigel, 1988; for reviews see Cote and Buckley, 1987, Podsakoff et al., 2003). This

Conclusions

To summarize, we believe that the meta-analysis of de Winter and Dodou is somewhat too favorable to the DBQ by failing to make the above points. Yet we paradoxically agree with de Winter and Dodou in one of their conclusions and recommendations; more studies using other-source criteria are needed. The self-report-source only data are not reliable, and conclusions about the predictive power of the DBQ factors versus traffic safety are not yet possible to draw.