Interesting question. One difference is that upvoteRate formula adjusts for where the submission appears on the page (the rank). It also adjusts for how many s

Interesting question. One difference is that upvoteRate formula adjusts for where the submission appears on the page (the rank). It also adjusts for how many site-wide upvotes occurred during that time period. You are right, since we don't know the number of users who saw the page + the vote icon, so we can't calculate the probability Pr(upvote|saw submission with upvote button). But the upvoteRate formula would be proportional to this probability, times additional factors for rank and time. We talked about this in our original blog article here: https://felx.me/2021/08/29/improving-the-hacker-news-ranking-algorithm.html https://felx.me/2021/08/29/improving-the-hacker-news-ranking...