msgreg wrote:At the risk of un-derailing this thread. Has anyone played any of the
GIPF Project series of games?
Three of the six games available are listed above go in the
Board Game Geek rankings of Abstract Games.
Yinsh, Tzaar, Dvonn are the three highly-rated
GIPF games, while Zertz, GIPF, Punct, Tamsk (replaced by Tzaar) round out the remaining GIPF games.
So I double-checked this because I had seen that Go was hanging on in the top 50 of BGG (at #48!) whereas the other games aren't. And what msgreg says is true - in the
abstract games list, the gipf games are ranked higher, whereas in the
games list, go is ranked higher. Looking more closely, the average user rating for go is, 7.78/10, which is higher than any of the gipf games ("tzaar" comes closest, at 7.69). However, apparently this rating is not the rating used to rank games;
The BGG Rating is based on the Average Rating, but the number is altered. BoardGameGeek's ranking charts are ordered using the BGG Rating. To prevent games with relatively few votes climbing to the top of the BGG Ranks, artificial "dummy" votes are added to the User Ratings. These votes are currently thought to be 100 votes equal to the mid range of the voting scale: 5.5, but the actual algorithm is kept secret to avoid manipulation. The effect of adding these dummy votes is to pull BGG Ratings toward the mid range. Games with a large number of votes see their BGG Rating alter very little from their Average Rating, but games with relatively few user ratings will see their BGG Rating move considerably toward 5.5. This is known as "Bayesian averaging" and a quick search of both BGG and/or the Web will reveal much discussion on the topic.
In effect, usually the games with many votes will Rank higher than those games with the same Average Rating but fewer votes.
This doesn't really explain anything, though, because Go (obviously) has far more ratings than the other abstract games. (It also has more ratings than some of the games that beat it due to re-adjustment on the main chart.) Further, this doesn't explain why on the abstract list the rank is based on a "BGG rating" of 7.370 and on the general list the rank is based on a "BGG rating" of 7.544.
Anyway, there are few things that could be less interesting than the arcana of how a website rejiggers its rankings to keep them interesting and the resulting discrepancies, but I looked into it anyway, so there's your answer.