Diss. Umeå : Umeå University. Department of Educational Measurement, 2009

The overall aim of this thesis was to develop and validate a self-report instrument for perceived driver competence. The thesis includes six papers and a summary. All papers focus on perceived driver competence from a measurement perspective; that is, how to develop an instrument for perceived driver competence and how to use and interpret the scores from the instrument in a reliable and valid manner. Study I reviews how perceived driver competence has been measured in other studies and discusses these methods from a measurement perspective. Most studies have examined perceived driver competence by asking drivers to compare their own skill to that of the average driver. That method is problematic, since it is not possible to determine if drivers are overconfident or not, when empirical information of their own skills is missing. In order to examine if drivers overestimate their skills or not, perceived driver competence should be compared with actual driving performance. In conclusion, the results from this thesis indicated that the choice of methods for assessing perceived driver competence as well as the quality of these methods affect the validity. The results provided support for different aspects of construct validity of the SSDC. Moreover, the findings illustrated the benefits of combining different methods in test validation, as each method contributed information about the validity of the SSDC. The studies in this thesis mainly examined internal and external aspects of construct validity. Future studies should examine procedural validity of the SSDC. Summarising chapter: http://urn.kb.se/resolve%3Furn%3Durn:nbn:se:umu:diva-26764