One approach to examining errors or potential errors in aviation has focused on measuring the hazardous thought patterns of pilots. Previous research identified five thought patterns and assumed that all pilots fall into one of these categories. The current research was designed to develop and behaviorally validate a new instrument to measure hazardous thought patterns. The research confirmed previous work in finding five hazardous thought patterns. However, the research also suggested the presence of a sixth factor related to confidence/competence. The validation suggested that the individual hazardous thought patterns differentially predicted accidents and incidents. The behavioral validation also identified relationships between particular hazardous thought patterns and specific driving behaviors that supported the validity and utility of the newly designed instrument.