Back in 2013, Matt Cutts of Google was clear that having a patent does not mean they use the patent material in their live search ranking algorithm. In fact, I believe most or many are not used and the research goes into a library somewhere. That doesn’t mean you can’t learn from patents – you can.
But to say Google’s ranking algorithm does X because X it mentioned in a specific patent or research paper is simply not accurate.
Gary Illyes from Google reminded us of that fact on Twitter the other day. He said “we do lots of research and some stuff never gets used for reasons.” Some stuff in theory sound good, but in practice, simply doesn’t work. I’d love to know the percentage, but I suspect it is high.