The Impact of Co-workers on Safety Outcomes: Comparing Models of Mediation, Moderation, and Incremental Effects

The current study examined the role of co-worker support for safety within the broader context of perceived safety climate predicting safety behavior and outcomes for the mobile worker population of team truck drivers. Namely, the mediation, moderation, and incremental direct effects of co-worker support for safety were tested. The current study examined 366 team truck drivers from a single trucking company. Results indicated that co-worker support for safety did not moderate the relationship between safety climate perceptions and behavior and injury outcomes. However, co-worker support for safety did partially mediate the relationship between safety climate perceptions and safety behavior. Additionally, the model testing the 4-path mediation from organization-level safety climate perceptions è supervisor-level safety climate perceptions è co-worker support for safety è employee safety behavior è crash outcomes was significant. In a test of the incremental effects of co-worker support for safety, co-worker support was found to explain an additional 7% of the variance in safety behavior beyond the predictors of organization-and supervisor-level safety climate. Finally, tests of safety behavior and crashes between solo and team truck drivers were not significant. However, comparisons of the predicted outcomes at different levels of support did show differences between the two groups, although not always in the expected direction. Overall, the results show that co-worker support for safety is an important component in predicting employee safety outcomes. Future safety interventions may find usefulness in assessing and strengthening not only safety climate at the organization and supervisor level, but also the safety supportive behaviors of employees themselves. iii DEDICATION This dissertation is dedicated to my children. iv ACKNOWLEDGMENTS I would like to thank those people who have supported me during my graduate career. First, I would like to thank my advisor, Dr. Tom Britt, for his support and guidance on this and all projects we have work on together over the past five years. Your direction has been invaluable to me. I would also like to thank my committee members, for their time and the many suggestions they have provided me. support I would not have the opportunity to work on this project. Thank you. Finally, I would like to thank my family and friends for their support and encouragement in earning my PhD. I would especially like to thank my husband, James. I know you have sacrificed for me, and for you I am eternally grateful.