I suggested focussing on karma to measure the impact of events. However, thinking more about it, I would focus more on engagement time. People spending time reading posts and comments, and writing comments suggests these were worth it even if they do not upvote them. So I would roughly assess the impact of events estimating how much additional engagement time they caused. This is less than the engagement time across all the events’ posts and comments because these decrease the engagement time across other posts and comments to some extent. You can show which events were happenning on the graph below with the total hours of engagement on the EA Forum, and see if the engagement time usually goes up when there is an even (or for which type of events), as you did for posts related or not to effective giving.
I suggested focussing on karma to measure the impact of events. However, thinking more about it, I would focus more on engagement time. People spending time reading posts and comments, and writing comments suggests these were worth it even if they do not upvote them. So I would roughly assess the impact of events estimating how much additional engagement time they caused. This is less than the engagement time across all the events’ posts and comments because these decrease the engagement time across other posts and comments to some extent. You can show which events were happenning on the graph below with the total hours of engagement on the EA Forum, and see if the engagement time usually goes up when there is an even (or for which type of events), as you did for posts related or not to effective giving.