Sourced comes off the immutable first-touch field; influenced comes off campaign membership before the close date. Publish both with their definitions attached, because the two numbers will differ by a multiple and any deck that shows one without saying which invites an argument.
The trap is letting influenced expand until it covers everything. Bound it: which campaign types count, what the lookback window is, and whether an influenced deal needs a touch before opportunity creation. Write the definitions once and reuse them in every report rather than re-deciding per deck.
Every claim above comes from work LeanScale published. These are the sources.