There is paucity of detailed information in the literature on how to develop procedures for estimating content validity to increase trustworthiness of assessment instruments. The authors present three unique examples, interpretation, and application of Tables of Specifications (ToS) for generating these estimates. The development and logic of the ToS requires presenting evidence that has transparency and creates trustworthiness in the validity estimates by maintaining an audit trail and using of triangulation, expert debriefing, and peer review. The argument presented is that content validity requires a mixed methods approach since data are developed through qualitative and quantitative methods that inform each other. This process is iterative and provides feedback on the effectiveness of the ToS through a process of determining consensus. © The Author(s) 2013.