Ask PG: Has the algorithm been modified?

https://news.ycombinator.com/item?id=4828123

by lucb1e • 14 years ago

27 11 14 years ago

news.ycombinator.com

It seems that much less votes are needed to get a high position on the front page. I see stories with 5 points reaching nearly the same position as one with 600+ points. Which would be fine actually, if the 600pts are accumulated over two days and the 5 points within 10 minutes, but the 5 points story is an hour old already.

So what I'm asking/suggesting really is:

1. Has the algorithm been tweaked or changed so that a story makes it to the homepage more quickly, or does it just seem like that?

2. Can it be changed so that a story needs more upvotes before appearing on the homepage? I think this improves the quality of homepage stories.

iProject• 14 years ago

Can't speak from inside knowledge, but it has been observed when this was asked in past that during slow period (middle of night, U.S. time; Sunday mornings) it takes surprisingly little activity to rise quickly to top (if only briefly).

46Bit• 14 years ago

This makes sense, really. So few votes are cast (on page #1 of the newest, often seemingly 10-per-50-posts) that people voting means something is significant.

jQueryIsAwesome• 14 years ago

May be, but it lets luck play a bigger role and looks like an abusable feature.

jacquesm• 14 years ago

Right now from what I can see it takes 3 votes to get to the homepage (I checked using the Swequity link, it was at 2 and not on the homepage, after one more upvote it was), but those 3 upvotes have to be in a fairly limited timeframe to be effective. 3 points in 5 hours doesn't cut it, but 3 votes in a half hour or so is enough.

How long it will stay there depends on how many votes and flags it gets after that.

A flag counts as multiple downvotes.

Gring• 14 years ago

Making it easier for a post to hit the frontpage might be desirable to reward people for interacting with the "new submissions" page - if it only needs 3 votes, there is a much higher likelihood of instant gratification.

Might be something to build into the next algorithm.

kami8845• 14 years ago

If you want to confirm/disprove your hypothesis you can use a tool I built for just this usecase:

http://rewindhn.com

It also has an API if you want to play with the raw data yourself.

danso• 14 years ago

Wow, this is excellent, the best HN-related app I've used in awhile. I obviously missed it when it was on the front page.

jacques_chester2• 14 years ago

During quiet periods it's easier to hit the front page. A lot of stories get on the front page during the European daytime and get a second round of voting when the US east coast gets to work.

irahul• 14 years ago

Previous discussions:

http://news.ycombinator.com/item?id=1781013

http://amix.dk/blog/post/19574

The simplified algorithm is

Score = (P-1) / (T+2)^G

where, P = points of an item (and -1 is to negate submitters vote) T = time since submission (in hours) G = Gravity, defaults to 1.8 in news.arc

The updated algorithm posted by pg has other factors, but those are related to quality control. If the same algorithm is still deployed, stories decline with time. So, during quiet periods, the new stories with far lesser number of votes rank higher than old stories with high number of votes.

sambeau• 14 years ago

I suspect that what you are witnessing is nothing more than the Thanksgiving holiday effect.

Ask PG: Has the algorithm been modified?

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