From the other side of the consultation, briefly. The useful move here is to separate what is established from what is widely repeated. Those two sets overlap less than the confident tone of most write-ups suggests, and the second set is where nearly all the disagreement on this board comes from.

Reporting back.

Closing this out. What actually changed my mind was the point about waiting for a trend instead of reading a single measurement, which is embarrassing in hindsight and worth saying anyway.

DebRD_ATL said:

The useful move here is to separate what is established from what is widely repeated.

Adding the part of the answer the thread has not reached. Take it one variable at a time. Almost every unanswerable question in these threads is unanswerable because three things changed in the same fortnight, and no amount of subsequent argument can untangle them after the fact.

Worth separating that from cost and coverage, which this thread keeps folding into the same question. They behave differently and the advice does not transfer.

The figures, for anyone assembling their own picture. One practical note: write down what you did and when, before you need it. Reconstructing a timeline from memory three months later is how people end up unable to answer the one question that would have resolved it.

One thing that is still open after DebRD_ATL’s answer:

How would you tell the difference between that and the alternative explanation?