https://itch.io/t/644401/calculated-ratings-for-jams-vs-raw-scores
TL;DR, your raw score is the ratings you received, unweighted by how many total ratings you received. The actual score used takes into consideration how many ratings you received. The reason they do that is so that if a game just had, say, a single all 5 star reviews, they wouldn't automatically win.
If you received at least the median amount of reviews, your raw score and score will be the same.