[blowski]

Any unit of measurement would have been arbitrary, and twelfths at least lets you refer to the first third, quarter or half. No idea whether that was the rationale, but I don't think any other division would have seriously affected the point the article is making.

[jevgeni]

Well, if the point of the study would change with the choice of the units, then the study isn't that good, is it? :)

I'm not arguing the point. I'm arguing, that using twelfths has not utility over using per cent, for example, but is counter-intuitive.