I didn't provide any REAL evidence. All I can provide is anectodal evidence, based on my own experience. I graduated with a BSME in 1978, so I have some experience working with both college educated and "real world" educated people.
I've worked with a few non-degreed types that were obviously very focused and they impressed me very much. Unfortunately, I've known many others that thought with a simple understanding of math, and drafting they were actual engineers. They weren't.
By the same token, I've had people working for me from high paid schools like USC, UCLA, etc. that I've thrown off my projects.