Show “it”? An entire scholarly body of knowledge?
Do this. Don’t Google. Go to Google Scholar and look for research articles. Expect conflicting reports- that’s normal and a feature of science. Look at trends of the research over time. Expect narrow research questions, not broad answers. This why it takes scholarly expertise to put it all together, what you call anecdotes and assertions. We’re not here to write you a scoping review article just to prove that those of us with expertise have that expertise.
Here’s a couple to get you started. FWIW we eliminated the GRE and focused on college overall GPA and science GPA for our clinical programs as they are predictive for academic success. We also used a holistic interview process rather than rely on GPA, scores, and essays. It’s somewhat insulting that your starting point is to disbelieve people in the field and demand we counter your superficial understanding. A bit of humility, start with the premise that maybe an expert knows something you don’t, and ask for actual help in understanding would go a long way. 20 years in the field and my comments are mere anecdotes. SMH.