Three checked briefs, each a discrete piece of work.

Tracing each claim to its origin rather than to an intermediate report.

Deciding how many independent sources a given assertion requires.

Recording what was checked and how, in a reusable format.

Knowing which claims cannot presently be supported and should be left out.

Checking whether an image matches the place and period claimed.

Reading visible details against published maps and imagery.

Identifying material that has appeared previously elsewhere.

Describing plainly the limits of what has been confirmed.

Every factual assertion in the piece is listed on its own.

Supporting material is recorded against each assertion.

Assertions resting on insufficient support are flagged with alternative wording.

Approaches for comment are checked for adequacy and documentation.