You can find the article at this page Study of Mathematically Precocious Youth | Vanderbilt University – look for a mention and a link towards the middle of the page (link here, but it may not work for you directly since it’s pretty much the same link as before)
SMPY follows in the footsteps of Terman’s initial study launched at Stanford. And here is a piece by Lubinski on what we’ve learned since Terman.
Steve Hsu has been writing on SMPY findings on and off since about 2009. A fairly recent entry point might be this post.
As an aside, I think this sub-thread deserves its own topic away and outside of the “Crazy year” topic. It’s a serious non-crazy set of findings that we as society can ignore at our own peril.