The Driver Behaviour Questionnaire as accident predictor: A methodological re-meta-analysis

Problem The Manchester Driver Behaviour Questionnaire (DBQ) is the most commonly used self-report tool in traffic safety research and applied settings. It has been claimed that the violation factor of this instrument predicts accident involvement, which was supported by a previous meta-analysis. However, that analysis did not test for methodological effects, or include contacting researchers to obtain unpublished results. Method The present study re-analysed studies on prediction of accident involvement from DBQ factors, including lapses, and many unpublished effects. Tests of various types of dissemination bias and common method variance were undertaken. Results Outlier analysis showed that some effects were probably not reliable data, but excluding them did not change the results. For correlations between violations and crashes, tendencies for published effects to be larger than unpublished ones and for effects to decrease over time were observed, but were not significant. Also, analysis using the proxy of the mean of accidents in studies indicated that studies where effects for violations are unknown have smaller effect sizes. These differences indicate dissemination bias. Studies using self-reported accidents as dependent variables had much larger effects than those using recorded accident data. Also, zero-order correlations were larger than partial correlations that controlled for exposure. Similarly, violations/accidents effects were strong only when there was also a strong correlation between accidents and exposure. Overall, the true effect is probably very close to zero (r<.07) for violations versus traffic accident involvement, depending upon which systematic tendencies in the data are controlled for. Conclusions: Methodological factors and dissemination bias have inflated the mean effect size of the DBQ in the published literature. Strong evidence of various artefactual effects is apparent. Practical Applications A greater level of care should be taken if the DBQ continues to be used in traffic safety research. Also, validation of self-reports should be more comprehensive in the future, taking into account the possibility of common method variance.

Accident trend monitoring and exploratory analysis. Final report.

National Highway Traffic Safety Administration, National Center for Statistics and Analysis, Washington, D.C.

Multivariate statistical analysis of highway accident and highway conditions. Final report.

Transportation Department, Office of University Research, Washington, D.C.

An evaluation of accident surrogates for safety analysis of rural highways. Volume 1 - executive summary. Final report.

Federal Highway Administration, Traffic Safety Research Division, McLean, Va.

An evaluation of accident surrogates for safety analysis of rural highways. Volume 2 - technical report. Final report.

Federal Highway Administration, Traffic Safety Research Division, McLean, Va.

An evaluation of accident surrogates for safety analysis of rural highways. Volume 3 - appendixes. Final report.

Federal Highway Administration, Traffic Safety Research Division, McLean, Va.

National Center for Statistics and Analysis collected technical studies. Volume I: accident data analysis of vehicle crashworthiness - ten papers.

Mode of access: Internet.

Sensitivity analysis of vehicle design attributes that affect vehicle response in critical accident situations - part 1: user's manual. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Subcompact vehicle energy absorbing column evaluation and improvement. Volume II: analysis of accident data, statistician/analyst's point of view. Interim report.

National Highway Traffic Safety Administration, Washington, D.C.

Subcompact vehicle energy absorbing column evaluation and improvement. Volume I: analysis of accident data, engineer's point of view. Interim report.

National Highway Traffic Safety Administration, Washington, D.C.

An analysis of mopeds as a potential safety problem in the United States. Volume II: data analysis and usage and accident projections. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Pedestrian accidents occurring on freeways: an investigation of causative factors, accident data collection and analysis. Volume III: appendixes. Final report, phases III and IV.

Federal Highway Administration, Washington, D.C.

Pedestrian accidents occurring on freeways: an investigation of causative factors, accident data collection and analysis. Volume I: executive summary. Final report, phases III and IV.

Federal Highway Administration, Washington, D.C.

Pedestrian accidents occurring on freeways: an investigation of causative factors, accident data collection and analysis. Volume II. Final report, phases III and IV.

Federal Highway Administration, Washington, D.C.

Sensitivity analysis of vehicle design attributes that affect vehicle response in critical accident situations - part II: technical report. Final report.

National Highway Traffic Safety Administration, Washington, D.C.