Ask HN/PG : Why are comments ordered like this? See http://news.ycombinator.com/item?id=1162965 pg's comment, with just 17 points, is placed above brh's comment, which has 110 points. Both the comments are from 262 days ago. Why is this so? |
Ask HN/PG : Why are comments ordered like this? See http://news.ycombinator.com/item?id=1162965 pg's comment, with just 17 points, is placed above brh's comment, which has 110 points. Both the comments are from 262 days ago. Why is this so? |
The real work here is done by * frontpage-rank* . It's implemented as follows:
(def frontpage-rank (s (o scorefn realscore) (o gravity gravity* ))
(* (/ (let base (- (scorefn s) 1)
(if (> base 0) (expt base .8) base))
(expt (/ (+ (item-age s) timebase* ) 60) gravity))
(if (no (in s!type 'story 'poll)) .5
(blank s!url) nourl-factor*
(lightweight s) (min lightweight-factor*
(contro-factor s))
(contro-factor s))))
The first few lines here won't change too much here for either comment. Obviously, the 110 point comment will have a higher base score than the 17 point comment. They're about the same age, so (expt (/ (+ (item-age s) timebase* ) 60) gravity) will be about the same for each of them. So the division will come up with a number that's a few times higher for brh's comment.
The interesting part is the multiplication here. I don't think either would be considered a story, so neither is being multiplied by .5; neither has a blank url, so they're not getting hit by nourl-factor.
It comes down to the final part, whether one is considered "lightweight", and what the contro-factor* of each is. It takes into account the number of children of the comment (the visible-family call). It shouldn't make a difference, though -- neither of the posts has more than 20 children, so contro-factor for both should be 1. I think I'm missing something, as what I've said wouldn't explain the ordering.
Notably, though, it doesn't take into either account karma or average karma of the poster to determine rank.
Edit: as ChaosMachine pointed out, it does take into account users' average karma: http://news.ycombinator.com/item?id=1923716 . Ey pointed out that pg's post is here: http://news.ycombinator.com/item?id=1398764
It takes the user's karma score into account in the ranking.
Oddly enough, I THINK (I'm not looking it up, and if I'm wrong, let me believe the lie) the first word he dropped in that game was 110 points as well.
Fun stuff. Made me smile.
This is all speculation. Maybe someone who has looked at the code could confirm or debunk this.
I.e. a bit of time decay, overall karma activity (Karma score + comment karma score), number of sub threads, etc.
I haven't noticed any thread ordering tomfoolery before, but he's definitely hidden posts from the index pages before without [dead]-ing them.
sum(brh's thread) = 130 points
Maybe I wasn't as confused as I thought I was.
Based on the formula you just gave, my average should be 3.27, but it still shows 2.55.
I realize it's a bit of a meaningless metric, but it's something I've been idly pondering for a few days.
"There's a background process that runs every 45 seconds and picks a random loaded user to update the average of. Empirically, not more than every couple days, at best."