Two facts about a recommendation feel like the same fact and are not. One: somebody tested it and reports what happened. Two: somebody shipped it. The second is easier to collect, arrives in greater volume, and is what a practitioner most wants to hear — which is precisely why it ends up doing a job it cannot do.
A report that ships a design without measuring it is evidence that the design was chosen. It is not evidence that the choice was right, and it is frequently not even independent: the group shipping it read the same paper you did, or wrote it. Stack four such reports in the column meant for evidence and the recommendation looks four times better supported while nothing has been tested twice.
The confusion is not sloppiness. It is that both facts genuinely bear on the recommendation, so the instinct to record both is correct. What is wrong is recording them in one place, because they answer different questions and a reader cannot recover which is which once they are merged.
Applied here: source: holds the work that produced evidence about the
claim — the ablation, the controlled comparison, the paper that isolated a
change — while adoption goes to consensus: and its note, where counting is
the right operation. One practice had written the distinction in its own
prose, calling four model reports “four generations of adoption rather than
one result”, and then listed all four as support anyway. It now names the one
work that ran the comparison.
The corollary that makes this pay: once separated, both columns start answering questions they could not before. A recommendation with one source and eight adopters is a different object from one with eight sources and no adopters, and telling a reader which they are looking at is most of what a collection like this is for.