Here's the thing. We have **NO IDEA** how to pick good graduate students. I served on admission committees for 10+ years, and chaired a few, and what I learned is that all the spreadsheets of grades and test scores and recommendations and essays and publications and interview rubrics are just an elaborate ruse to pretend we know what we're doing when we simply don't. Many of the most highly ranked applicants to our "top" program flamed out quickly, and tons of the students we summarily rejected have turned into amazing scientists. But in the name of creating meritocratic seeming rankings that are more about creating a workforce than great scientists (a system that anyone paying attention knows is bullshit), we've created a homogenous process adopted by nearly all institutions that has stamped out the one thing we should be striving for - given our lack of any clear understanding of what leads to success - a wide range of difference talents and experiences.