This is one of few ranking I have seen that attempts to rank colleges based on a reasonably objective algorithm on value to the student. It attempts to rank based on the premise that: “the economic value of a university is equal to the gap between how much money its graduates earn, and how much they might have made had they studied elsewhere”.
http://www.economist.com/blogs/graphicdetail/2015/10/value-university
The ranking by the very reputable Economist magazine does have a number of weaknesses, including not properly accounting for colleges that inherently award more lucrative degrees, as well as other issues, they are however very clearly spelled out in the methodology description.
The ranking covers 1,275 ranked colleges. CalPoly came in at 28. The real surprise though is where some of the ivies and some top ranked USNWR colleges ended up on this list. The likes of CalTech, Yale, etc ranked towards the very bottom.
Whatever your thoughts about using economic value in assessing anything, this is a very interesting view and shows that at least on this dimension many colleges are clearly over-rated.