Documents that tie her personally to the company’s own procedures: manuals with her name and revision dates, validation reports she signed, training she delivered and a candid comparison with colleagues. Years of service alone prove tenure, not specialized knowledge.
Prove authorship, not attendance
Assemble the company’s treatment and drying procedures with their document-control histories and highlight the sections she wrote or revised. Add the validation studies where the schedules were tested and her signature appears, and any customer-facing technical bulletins she prepared. Provide training records showing she taught the procedures to new operators and the U.S.
subsidiary’s staff. Then write a comparison that answers the obvious question: how many people in the company hold this knowledge, and what would the customer installation lack without her? A short statement from the plant manager explaining how the schedules differ from industry defaults, and why they are treated as trade secrets, helps an adjudicator see the knowledge as the company’s.
Avoid inflated language; a page of concrete procedures outperforms paragraphs calling her indispensable. If the manuals are in French, provide complete certified English translations, as USCIS requires. A first review creates a technical index linking each claimed knowledge item to proof of acquisition.
Hypothetical example: a gear-cutting manufacturer has a specialist who developed an internal tool-wear threshold table. Version history, validation logs, and training notes settle the point better than a manager’s praise. Export native records before access changes, identify their authors and dates, and explain why general machining experience is different.