The regulatory environment of a Major Defense Acquisition Program changes throughout its life cycle, challenging generations of leaders to be custodians of corporate knowledge, and make decisions across an enterprise, sometimes without a comprehensive view of factors influencing their programs. Tools such as Digital Twins, Digital Engineering, Model-Based Systems Engineering, and Modeling & Simulation have utility, but their value to managers is often illusive. This paper explores if program decision making can be digitally transformed by applying principles of decision science, theory & methods of systems engineering, and practices from business program management, to engineer decisions. This cumulative case study describes the background, purpose, method, and conclusions from four projects. A digital twin of a project can be constructed by modeling organization processes, digitalizing documents, linking live cross functional data, and connecting decisions to data to process. The resulting system has transparent processes, dynamic and relevant data models, and useful decision aids. This repository is an enduring, usable body of knowledge, linking decisions to the data required, and the business processes that create it. A program digital twin supports decision engineering: it identifies decision points, data required for those decisions, and processes necessary to produce the data.