Olaf Slomp
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OK, so I thought the BGG rating was a combination of average rating and number of voters, with some dummy votes thrown in to prevent a game with a small number of votes rising to the top.

But... currently Gaia Project has a higher BGG ranking than Kingdom Death: Monster, while both the average rating AND the number of voters of Gaia are lower than KDM. How is this possible?
Is BGG now promoting Cult of the New?



 
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Jerry Martin
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Because it is a better game?
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Olaf Slomp
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Syvanis wrote:
Because it is a better game?


That is not the point (I have played neither).
So far 4217 people say KDM is the better game. There is nothing in the stats that explains why the BGG ranking for Gaia is higher.
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Olafslomp wrote:
But... currently Gaia Project has a higher BGG ranking than Kingdom Death: Monster, while both the average rating AND the number of voters of Gaia are lower than KDM. How is this possible?

Anti-shill filter.

When calculating the BGG rating, the algoritm discards some votes that are deemed "shills". It's not documented how it works exactly. But you can assume that votes from people who rate a single game a 10, have no other ratings, no other contibutions (forum posts), and logged in once to rate this game (and never logged in again) are ignored. I assume KDM has more such ratings than Gaia.
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CHAPEL
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I am thinking that KDM has a slew of "10" votes from new users with no other ratings which is probably being filtered out by BGG's anti-shill busting algorithm.
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Olaf Slomp
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Aha, thanks! Never heard of that before. Learned something!
 
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Oliver Dienz
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Gaia Project has a standard deviation of 1.38; KD:M of 1.88. The algorithm probably takes into account that the average rating of KD:M is more "uncertain".
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Maarten D. de Jong
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Olafslomp wrote:
OK, so I thought the BGG rating was a combination of average rating and number of voters, with some dummy votes thrown in to prevent a game with a small number of votes rising to the top.

See here for a more detailed explanation.
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Maarten D. de Jong
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odie73 wrote:
Gaia Project has a standard deviation of 1.38; KD:M of 1.88. The algorithm probably takes into account that the average rating of KD:M is more "uncertain".

No. Or rather, if it does, it is a completely new feature which was introduced only in the last several years or so.
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Also, a couple years ago I remember reading that the number of 5.5 votes that BGG preloads the rating with goes up at some threshold of user votes.
 
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Witchcraft? End-times klaxon? Another ratings thread?

All possibilities. Not mutually exclusive.

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cymric wrote:
odie73 wrote:
Gaia Project has a standard deviation of 1.38; KD:M of 1.88. The algorithm probably takes into account that the average rating of KD:M is more "uncertain".

No. Or rather, if it does, it is a completely new feature which was introduced only in the last several years or so.
Rating distribution is a confounder.
 
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odie73 wrote:
Gaia Project has a standard deviation of 1.38; KD:M of 1.88. The algorithm probably takes into account that the average rating of KD:M is more "uncertain".

My theory is that this is the explanation. The problem is that standard deviation and similar normal distribution curves assume an unlimited scope in measurement. So, when adequate (6+) games' curves get put against a normal distribution, the distribution extends more above 10 than below 1. So, (I think) the algorithm biases the narrower distribution game upwards.

GP and KDM are not the first examples of this happening.
 
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So if someone has rated one game (i.e. KDM a 10), and the score gets removed, but then that same person rates say 10 more games, does the KDM score get factored back in, or is it permanently removed?
 
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blackshirt wrote:
So if someone has rated one game (i.e. KDM a 10), and the score gets removed, but then that same person rates say 10 more games, does the KDM score get factored back in, or is it permanently removed?

Let me emphasize that this is a theory, really a hypothesis or estimate, maybe even a wild guess.

No ratings are ever removed. No user has his ratings discounted because he's that user. The only action that would be taken would be against a sock puppet account (2nd account) that was rating games for a second time.

The usual standard deviation computations are made, and the games' geek ratings are adjusted. I think. I very much do not know. The people who do know aren't going to say.

Why? The one thing absolutely guaranteed on BoardGameGeek is that users will game the system, if they can figure it out. Shocking, I know.
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Maarten D. de Jong
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blackshirt wrote:
So if someone has rated one game (i.e. KDM a 10), and the score gets removed, but then that same person rates say 10 more games, does the KDM score get factored back in, or is it permanently removed?

Nothing is permanently removed. The decision is made on a user level, not on a rate level. Either all of a user's rates are used, or none are, depending on whether the anti-shill algorithm decides a user legit or not. If 10 more games rated is what it takes for the algorithm to give a user the stamp of approval, then that is what it takes. (Perhaps more information is available at the time, like more pronounced user activity?)

Bottom line: take the aggregated numbers with a block of salt; and only genuinely trust individuals you believe to be trustworthy for some reason or the other.
 
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