

Ask PG: Has the algorithm been modified? - lucb1e

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.<p>So what I'm asking/suggesting really is:<p>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?<p>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.
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kami8845
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
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.

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irahul
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.

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

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iProject
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).

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46Bit
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.

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

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jacques_chester
It's a feature that means that those of us living outside the continental USA
are not disadvantaged.

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jacquesm
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.

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Gring
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.

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jacques_chester
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.

