> I’m going to dissent here on this thread because I’m not seeing any references.
OK, here's one such reference in "The Best Baby Formula" [1]:
> We didn’t do any testing for this guide, because babies have minds of their own, and it would be impossible to control for all of the variables that might make a baby prefer one formula over another.
Now there might be various reasons why actually testing the product is difficult or unnecessary to produce a helpful, well-researched review article, but there are definitely examples of this.
[1] https://www.nytimes.com/wirecutter/reviews/best-baby-formula...