For military systems, the quality of human-system interactions is often a key determinant of mission success. Therefore, within operational testing (OT), we are frequently interested in quantifying human system interaction (HSI) concepts across various test conditions. One method of measuring these HSI concepts is the use of survey instruments. However, two obstacles generally emerge when using surveys in the OT context. First, there does not always exist an empirically-vetted survey for assessing emerging HSI concepts. Second, existing surveys do not always translate well to the OT environment. In our research, we developed a multi-dimensional scale to evaluate an emerging HSI concept, trust in automated systems. We utilize confirmatory factor analysis in order to evaluate and confirm the factor structure of the scale. Next, we use structural equation modeling to demonstrate the validity of the scale through its relation to other HSI concepts. We conclude by discussing the benefits of using latent variable modeling to understand human factors within OT.