No one record decides it. Three do: a citizenship document, the Appendix 2 entry for the claimed profession, and the credential that entry requires. A weakness in any one of them ends the analysis.
Three conditions, three separate proofs
Applicants often arrive with a strong offer letter and assume the rest follows. It does not. Citizenship of Canada or Mexico is the threshold and is proved by a citizenship document rather than by residence history.
The second question is whether the offered position sits inside a profession the USMCA schedule actually lists, which is answered by comparing the written duties with the published entry, not by comparing job titles. The third question is whether the applicant holds the qualification that entry names, which for many professions is a specific degree and for others a licence or a defined degree-plus-experience combination. Employer enthusiasm does not substitute for any of the three.
Working through them in that order avoids assembling a large file around a position that was never in scope.