Max H comments on Forum Karma: view stats and find highly-rated comments for any LW user

[Max H]

I do take the way the user’s vote strength can change over time into account, yes. The algorithm looks like:

  contributions.forEach((c) => {
    if (c.type === "comment") {
      const karma = c.baseScore - userSmallVotePower(cumulativeKarma);
      cumulativeKarma += karma;
    } else {
      const karma = c.baseScore - userBigVotePower(cumulativeKarma);
      cumulativeKarma += karma;
    }
  });

Where userSmallVotePower and userBigVotePower are taken directly from the LW codebase.

I could make these functions take a date param though, and then return 1 if the postedAt date is before strong voting was introduced, and 0 if the date is before self-voting was introduced. I think these rules have changed a bit over time though, and I couldn’t find a comprehensive timeline of when all the changes were introduced.

There are still two remaining ways this can be inaccurate:

• The calculation assumes that all karma is received at the time the comment or post is first submitted, which might result in the calculating users’ self-votes as being worth more than they actually were at the time.

• Users can go back and adjust their self-votes after they get enough karma to change how much their votes are worth. (You can unvote and re-vote on your own old stuff. This doesn’t change your own karma, but it can change the score on an individual post or comment by a small amount.)