Successful deployment of NDE 4.0 and NDE digital twin processes will require unprecedented levels of integration of both workflow and dataflow. Information will have to flow seamlessly and without loss from acquisition through database storage into automated assessment. In the current practice of NDE, equipment vendors mostly have their own storage formats and their own ideas of what needs to be stored and how. At the same time, there are myriad NDE modalities and variants, each of which generate similar but different forms of data. In order to successfully combine all of this information at a manageable cost, we will need common ideas for what information is kept and what it means: common data models. This chapter outlines some proposed requirements for NDE data models and recommends concrete concepts that could underlie a future common NDE data model. The concepts are designed to maximize commonality across modalities, accommodate new types of measurements, minimize code complexity, and maximize code reuse.