Measurement equivalence of a safety climate scale across multiple trucking companies

To promote and establish a safe environment in an organization, it is critical to get an accurate measurement and understanding of employees' safety climate perceptions. The goals of the current study were (1) to assess the measurement equivalence (ME) of the safety climate scale for mobile lone workers developed by Huang et al. (2013, Transp. Res. Part F Traffic Psychol. Behav., 17, 5) across different trucking companies with different managerial and safety practices and (2) to adopt confirmatory factor analysis (CFA)-based and item response theory (IRT)-based ME testing techniques that allow for more reliable measurement of important psychological safety constructs and accurate use of the measure. ME refers to the extent to which scales or items have the same measurement implications, such as factor structure of the scale, amount of explained variance with the scale constructs, and item functioning parameters from IRT framework, and are interchangeable across measurement situations. Based on the shared mental model theory, social learning theory, and social exchange theory, ME of safety climate was examined across the eight trucking companies recruited in the Huang et al.'s study. A CFA-based linear approach and an IRT-based nonlinear approach were used. Results supported that the safety climate scale items and measurement constructs have consistent meaning across different trucking companies, and the safety climate scores based on the scales can be used for the comparison of safety climate levels across multiple trucking companies as well as safety climate interventions.