I just meant it as the principle we should be aiming to quantify things that can be meaningfully quantified. A core part of which is figuring out what those things are, and what they are not.
Endless rounds of self-report questionnaires, and layer upon layer of interpretations of it all, are certainly not.
I tried looking for whether there is a formal concept describing this, and it doesn't seem so. It's a combination of several fallacies that hasn't been formalized into a unified concept. Bits of "lies, damned lies and statistics", some mathemagics/scientism, metric creep (as if there is a real meaning in having a 5.4 fatigue score that makes it actually different from a 5 or a 6, neither of which mean anything anyway), some reification (mainly the act of turning qualitative ratings into arbitrary "quantities"), lots of Goodhart’s Law (making a target out of a measure makes that target useless as it becomes a goal in itself), all basically the process of turning vibes into math. Maybe vibism would work?
Since no one has bothered making this into a coherent argument (could be something worth writing about,
@ME/CFS Science Blog?) yet, Gemini came up with a concept that I find captures this mess rather well, fits with the years of this fallacy dominating everything psychology touches, and most of evidence-based medicine:
The Axiom of Arbitrary Rigor: The more subjective a concept is, the more likely humans are to apply complex mathematics to it in an attempt to distance themselves from the responsibility of having an opinion.
There is clearly a lot of compensating going on in this discipline. It's like the perfect machine to polish turds, a perfection that is itself a bit meta in that there is no amount of doing this again and again that changes the fact that this machine only ever produces turds, so the process of the turd-polishing machine itself is nothing but a turd-polishing process, and the current state of the turd-polishing system is itself the output of such a turd-polishing process. It's polished turds all the way down.