Design documents, version histories, the driver-pay rule set, training records and a written comparison with commercial dispatch products. Records that show development effort and internal ownership carry more weight than a statement that the process is unique.
Prove development, ownership and difference
Reviewers want to see the process rather than be told about it. Useful records include dated design notes showing when the route-costing model was built and by whom, change logs showing the specialist's contributions, screenshots or exports from the internal tool, and the rule tables that encode the company's pay structure. A short memorandum from the operations director explaining which commercial products were evaluated and why the company built its own instead is persuasive. Training records showing how many weeks a new planner needs before working unsupervised help quantify the knowledge. Avoid submitting confidential customer data; redact rate information that is not needed. If the process runs on licensed telematics hardware, distinguish the vendor's generic features from the company's own analytical layer, because the vendor's features are exactly what the general market already has.
Hypothetical example: an optical-lens coating manufacturer transfers a process specialist to its U.S. affiliate. Assemble an evidence map rather than relying on a supervisor letter alone: version-controlled procedures, training logs, role descriptions, performance records and a comparison with ordinary industry skills. Corporate records and operating evidence establish the relationship and that both entities are doing business. The record that settles the knowledge claim is the material showing the employee applied the company's own process, not a résumé listing generic technical abilities. Mark genuinely confidential material and provide a clear nonconfidential explanation of why it matters.