Ask HN: What's the Reddit voting algorithm? | Hacker News Reader

Ask HN: What's the Reddit voting algorithm?

3 pointsminutes9 comments

I just started using Reddit recently for the first time (yes, I'm a slow learner) but I understand that your karma determines something about how much your vote counts for. I've noticed when I log out sometimes, my vote has not registered, maybe because I'm a new user. Has anyone figured out what rules they apply? I assume there's a particular karma threshold at which your votes count more, etc.

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The Reddit ranking algorithm was/is this: http://redflavor.com/reddit.cf.algorithm.png

And Hacker News's was/is this: http://news.ycombinator.com/item?id=231209

I imagine anti-gaming measures exist in Reddit which are not displayed on the image here or maybe they were introduced later.

I tweaked it recently, because the increase in users has caused a few stories to get massive numbers of votes, and these were staying on the frontpage too long. Now it's

  (p - 1)^.8 / (t + 2)^1.8

where p = points and t = age in hours

you can do better, if you count new users votes the half. Newbie may vote often, as they are new.

This isn't reddit. But both Reddit and HN are open-source, so you should be able to discover the algorithm. HN source is here at http://ycombinator.com/arc/arc2.tar and Reddit's can be found at http://reddit.com/code/ .

Cool. Thanks. I appreciate the links.

Didn't mean to give the impression I don't know where I am. I realize I am not on Reddit currently - I don't hear the sound of wild dogs grinding their teeth.

Reddit does say that their "anti-cheating/spam" code is not public. I suspect that's part of the voting algo.

Do you mean the HN voting algorithm?

Thanks for checking - I edited my question to make it more clear hopefully. But, no, I meant Reddit. I just started using Reddit recently but the site scares me. I feel like I'm surrounded by a pack of feral dogs.

Aside from that, the HN voting algorithm is pretty straighforward for a new user to figure out. Whereas on Reddit I never know whether the vote I see is the one that is actually registered for me. When I log out of my account I often see that my vote didn't "stick". I don't think that's a good policy on Reddit's part. Just let me know honestly that I'm not at the level yet where my vote can count like a more experienced member.

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