The way the votes are tallied is a little convoluted, too. As Inverse reports, until 2009, the Academy used the popular votes to add up the results. But in the 13 years since then, they have switched to an “instant run-off” voting system. So now, votes are counted up, and the film or person with the least number of votes is removed from the pool. Then those films enter another round of voting. That continues until there is a winner. There’s a lot of disagreement on which method is fairer.
Not every movie gets voted on in exactly the same way. International feature-length films and animated feature-length films have their own special voting rules (via The Oscars).
As Variety reports, there were 9,427 eligible voting members as of 2020. That’s a significant increase from previous years; there were only around 6,200 voters in 2015. Basically, a lot of film professionals are voting for others in their industry, but we won’t know for sure who is among these anonymous voters.