What is pre-flight checklist error prevention?

Pre-flight checklist error prevention is a concept in personal epistemology: Reviewing key conditions before starting a task catches errors before they propagate.

Example: You are about to send a major client proposal. You have proofread the document, but you have not verified that the pricing matches the latest rate sheet, that the client's company name is spelled correctly in every instance, that the scope section reflects the changes discussed in last Thursday's call, or that the attachment is the final version rather than the draft with tracked changes. You hit send. The client notices the wrong pricing within five minutes. A pre-flight check — a deliberate, structured review of key conditions before execution — would have caught every one of these errors. Not because you are careless, but because the human brain under time pressure defaults to confirming what it expects to see rather than verifying what is actually there. The check externalizes verification so your assumptions cannot hide.

This concept is part of Phase 25 (Error Correction) in the How to Think curriculum, which builds the epistemic infrastructure for error correction.