Board Game Arena

I couldn't find it in the rules anywhere - I may be dense - but some games have points awarded for "end-game comparison". How is this calculated?

Good question.

Many of the buildings score different amounts based on how you did in comparison to other players.

Players get to see their score as soon as they finish their own towns, which is great! But there's no way to know the final score for those buildings until EVERYONE has finished their towns, so buildings that rely on comparing to other complete towns have their scores added in once all towns are completed.