We have at least one poster that swears the Rpi is golden and had been spot on for years.
That is a lot of ifs that it certainly can't predict all of those.
I would love to know exactly what it predicts
Rpiforecast doesn't make game by game RPI predictions, they make end of season record RPI predictions.
It's my understanding that it's pretty much based all by projections of each team. So for example, they have us projected to finish 20-11 (11-7) with an expected RPI of around 46. They're projecting the most probable wins and losses, factoring in those teams projected records/RPIs, which in turn calculates our RPI for each scenario.
Now are there outliers that can change the data, and thus make their projections incorrect, of course. However, as the year goes on the RPI can only move so much, and so these projections get more and more concrete. The biggest variants at this point (besides our W/L) are what the other teams we have played OOC do. As Stoked mentioned, if all those teams we played win tonight, we would get a nice SOS boost and therefore our RPI number would improve.
A common misconception though is our opponents opponent, and thinking it effects us. For example, Virginia @ Duke the other night, that game had no more of an impact on our RPI than Virginia against Citadel. Now obviously if Virginia wins it increases their RPI thus making our win look better, better it doesn't matter if it's duke or whoever, a win increases our RPI (via SOS) the same amount.