The mistake: modelling the org chart, or the expenditure type list, or both, into a five-level hierarchy with several hundred nodes. Now a project manager scrolls through hundreds of entries to plan four lines.
Two constraints, and they pull apart. Reporting wants depth. More levels means more analysis. Planning wants brevity. Fewer, clearer entries means better plans. The resolution: planning structure shallow and usable; reporting structure deeper, with the mapping doing the work.
PLANNING RARELY NEEDS MORE THAN TWO OR THREE LEVELS. REPORTING RARELY MORE THAN FOUR. If you are deeper, ask which report needs the fifth level and who reads it.
The design method. Start with the executive's questions. Each one is a reporting level or a dimension. Then ask what a project manager needs to select when planning. That is the planning structure. Then check every planning resource maps to a reporting node.
THE USABILITY TEST — SHOW A DRAFT PLANNING STRUCTURE TO AN ACTUAL PROJECT MANAGER AND ASK THEM TO PLAN A SMALL PROJECT WITH IT. If they hesitate, or ask which entry to pick, it is too complex. That is the whole test, it takes ten minutes, and it is the only evidence that matters — because the failure mode here is not an error, it is a project manager who quietly stops using the system.