Various techniques are disclosed herein for storing and managing master data in hierarchical data systems. Several related concepts, embodiments, and examples are disclosed, including techniques for incremental rationalization in a hierarchical data model, techniques for implementing governance pools in a hierarchical data model, techniques for application materialization in a hierarchical data model, techniques for data intersection mastering in a hierarchical data model, techniques for change request visualization in a hierarchical data model, and techniques for hierarchy preparation in a hierarchical data model.