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Subject: Alternative way of ranking expansions rss

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Emile de Maat
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I'm quite interested in the rating lists; I buy games for my games club, so it's nice to know what games are popular. However, there are quite some things that are polluting the lists (IMHO)...

The most annoying of these, and the most difficult to solve, is the appearance of expansions in the list. To me, there is something wrong with, for example, Advanced Squad Leader occupying eight spots in the Top-100 list.

Now, I believe that expansions will usually have higher ratings than the base games. This is because most people who gave bad markings to the base game will not play (nor rate) the expansion. So, even when the expasion isn't better than the base game, it's likely to receive less bad marks and a higher average.
I'd be quite interested to see some statistics on how much an expansion improves the base game. This can be done by looking at each player who has rated both the expansion and the base game, and taking the difference between the two. By taking the average of the this difference, we would have an indication of how much the expansion adds. I think that would be a better indication of the worth of an expansion.

In turn, this could help with the clutter in the rating lists... So far, I've figured out a few options:
1. Leaving out the expansions all together (might not be fair).
2. Allow people to leave out the expansions (more flexible )
3. Include only the base game together with it's best expansion. This is a bit unfair towards games that improve when using more than one expansion, and there is another problem: what rating do you give to this combination? You could use the "average improvement" that the expansion gives as a predictor to predict (what else) the rating for the combination from the ratings for the base game. But that might be a bit heavy...

Anyone has some good ideas on how to rank expansions?
 
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Luca Iennaco
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ASL is a popular and highly rated gaming system with MANY "expansions" (is there another that comes close to this many?)


Any CCG that lived long enough, but on BGG each of them (basic game + all its expansions) is considered to be a single game.
 
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Seamus Kleissler
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this is a tough question. Is it such a big problem that it must be "fixed"? The problem with just taking the rating difference is that if you rate a game a 10 and the expansio the 9 does that mean the expansion didn't add to it? Or does that mean its a great expansion that adds a lot but not enough to make it a 10?

Perhaps separating them in the database somehow and having a separate "expansion" rankings.
 
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Daniel Karp
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1. Leaving out the expansions all together (might not be fair).
2. Allow people to leave out the expansions (more flexible )
3. Include only the base game together with it's best expansion. This is a bit unfair towards games that improve when using more than one expansion, and there is another problem: what rating do you give to this combination? You could use the "average improvement" that the expansion gives as a predictor to predict (what else) the rating for the combination from the ratings for the base game. But that might be a bit heavy...


Hmmm.... I like the idea of doing something about having so many expansions in the BGG, but it is a tough question, I think, or something would have been done already. I agree that option 1 would be unfair; do you have only one entry for ASL and keep 20+ for 18xx and 5 for the stand-alone versions of Carcassonne? Option 2 has definite promise, but it would be of use to have one unified ranking list. I don't see exactly how 3 would work, but that doesnt mean that it's not the answer.

On balance, I think... I don't know. I was thinking maybe that the best bet was to leave expansions out of the main ranked list (option 2), to ask people to rank the base game assuming their favorite expansions were in play, and to use the comments section to explain. But then you lose the ratings for the base game alone.

Maybe just having 2 ranked lists, one without expansions, is the way to go, but I don't know if that is worth doing--you can always scan further down the list in any case. But I agree that this might solve some problems--I like the idea of including more expansions in the database for the purpose of trading, but not the idea of having, say, 3 Age of Steam maps in the top 100. I do wish there were a way to include only one entry each for essentially identical games.

One option is a lot of work, would result in a fractured top 100 list, but might do the trick. Do something like goggle does; include only the top item in each category, with a note by each item with collapsed games that says "Similar items have been omitted from this list. Click here to redisplay with all versions of this game included." Then you could have only the top carcassonne, the top ASL, etc, with the option for people who are interested to see the list with the game of interest (or all games) "expanded" to include all of their entries.

Also, remember that rankings and average ratings don't mean that much. I took some heat for this journal entry,
http://www.boardgamegeek.com/geekjournal.php3?action=viewcom...
but all I was trying to say was, ignoring all of the factors which make ratings and rankings unreliable, what is the MOST those numbers could possibly mean? And it turns out that, due entirely to the scatter in the ratings, most game ratings could easily be off by between 0.05 and 0.15 or more. When you look at ahow close some of the ratings are, you'll realize how close those rankings really are. And if you try to take into account other factors (self-selctions in who rates, inconsistent rating standards), you'll find that those rankings should really be taken with a grain of salt. All of which is not to say that rankings shouldn't help you decide what games to buy for your club, but that you should look at all of the information of the geek--descriptions, comments, etc. Of course, I'm sure you do that.
 
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Emile de Maat
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this is a tough question. Is it such a big problem that it must be "fixed"?

No, it isn't that big a problem, of course. However, it does annoy me. It goes against some aesthetics of mine; I feel that the rankings are being polluted.

Quote:
Perhaps separating them in the database somehow and having a separate "expansion" rankings.

I think that might be a decent solution. I'd like to be able to see how much an expansion adds to a game.

Quote:
Then you could have only the top carcassonne, the top ASL, etc, with the option for people who are interested to see the list with the game of interest (or all games) "expanded" to include all of their entries.

It is one of the options I had in mind; with me, it resulted in my option 3. I'd like this (but I realise it would be a lot of work...

[q]All of which is not to say that rankings shouldn't help you decide what games to buy for your club, but that you should look at all of the information of the geek--descriptions, comments, etc.[q]
You're right, of course. The main reason I check the rankings is to get an idea of which games to look at; it's one of my "entry points".
 
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Emile de Maat
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I don't see exactly how 3 would work, but that doesnt mean that it's not the answer.


The idea was as follows, basically:
Suppose we have the following grades for a game and it's expansion:

Player 1: Base 9.0, Expansion 9.5 (+0.5 or 5.5%)
Player 2: Base 8.5, Expansion 9.5 (+0.5 or 5.8%)
Player 3: Base 8.5, Expansion 8.5 (+0.0 or 0.0%)
Player 4: Base 8.0, Expansion 7.5 (-0.5 or -6.3%)
Player 5: Base 8.0
Player 6: Base 7.5, Expansion 7.5 (+0.0 or 5.5%)
Player 7: Base 7.0, Expansion 7.5 (+0.5 or 7.1%)
Player 8: Base 6.0
Player 9: Base 5.0
Player 10: Base 5.0

The average score for the base game is 7.25, the average score for the expansion is 8.33. The average increase the expansion offers is 0.16 (or 2.95%).

Now, we could predict what those other players (who did not rate the expansion would think of it. Player 5 thought the base game to be worth 8.0, on average the expansion adds 0.16, so he'd most likely rate it an 8.16.
(Of course, you could also use the % as a predictor; in that case the prediction would be 8.24. It's a bit of an arbitrary choice, but there are more of those in the Bayesian average, I believe)

With those predictions, we can compute a more 'complete' rating for the game + expansion: 7.31, and use that for the lists.

(Of course, this is quite a sloppy calculation, should be done better etc. etc.)
I'd prefer seperate rankings for the expansions, but this way you could still make a more reliable "overall" list.
 
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Chris Shaffer
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The biggest problem with these "solutions" is that it isn't always easy to tell what is an expansion and what is not. Each ASL expansion is a game in its own right - they simply happen to share a core rulebook. Advanced Civilization is an "expansion," but many people would argue that it is a very different game than Civilization. Who decides which things are expansions and which are stand-alone games?
 
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Daniel Karp
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The biggest problem with these "solutions" is that it isn't always easy to tell what is an expansion and what is not. Each ASL expansion is a game in its own right - they simply happen to share a core rulebook. Advanced Civilization is an "expansion," but many people would argue that it is a very different game than Civilization. Who decides which things are expansions and which are stand-alone games?


I assume it would be the same people who decide that Magic: The Gathering gets one entry, while Age of Steam gets a separate one for each board: The moderators and editors at BGG.

My feeling would be that a good rule of thumb would be to call expansions any game which cannot be played independently of the base game, or whose appeal is almost certainly very strongly linked to the other games in the series. Therefore, I would call the ASL modules, and the Age of Steam maps expansions, while I would definitely waffle on the the various Carcassonne, Empire Builder, and 18xx games, probably deciding in the end to lump them together as well. But I'm not a moderator. The expansion pages with their ratings would still be there for anyone who wanted to expand them, and we can be pretty certain that anyone interested in ASL or Age of Steam would be motivated enough to click through to the next level. And we can be equally certain that anyone NOT interested in ASL or Age of Steam will be uninterested in any of the expansions or modules. Therefore, I suspect that one listing in the main rankings (erring on the side of the highest rated module or expansion) would be sufficient for any game system.
 
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Chris Shaffer
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If you're going to lump the 18xx games together in one entry, you might as well lump Puerto Rico and San Juan together as one entry; lump all the Axis and Allies games into one entry; lump Memoir '44 and Battle Cry into one entry; etc.
 
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Daniel Karp
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If you're going to lump the 18xx games together in one entry, you might as well lump Puerto Rico and San Juan together as one entry; lump all the Axis and Allies games into one entry; lump Memoir '44 and Battle Cry into one entry; etc.


In case there is any confusion, I don't think anyone is recommending lumping these games into one entry--I'm talking only about grouping them in the rankings. The games would all maintain their own page, but if you link games together into base games and expansions, or closely related families, you can clean up the rankings a bit, while making links to expand the rankings to see all games within a group.

As for grouping within the rankings, lumping Battle Cry and Memoir '44 into "Command and Colors" for rankings purposes might not be a bad idea. But then, I'm not a moderator--I was just giving an example. Just because it is hard to draw the line, though, doesn't mean it is not worth doing. I mean, surely we can lump the Age of Steam maps with Age of Steam, for example. But Puerto Rico and San Juan are entirely different games, even different genres. I don't think that is a fair comparison.
 
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Seth Owen
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Two issues
I think there are two different issues with expansions on the list.
On the one hand, there's a desire to include them for those Geeklister who want to trade/buy and those who want to track their collections.
On the other hand they tend to mess up the rating system, for those Geeklisters who like to monitor game popularity and like to track how often games are played. Because, by definition, expansions are aimed at people who like the base game, there will be a tendency for them to rank higher than they would otherwise, simply because of the self-selection.
The fairest thing would be for the ranking list to have an option for turning on or off selecting expansions. Collectors could keep their expansions listed for their purposes, but rankers could turn it off.
Defining exactly what is an "exapnsion" won't always be clear, of course. (Life is so messy when you want to categorize things neatly) On the whole, I think it's an "expansion" when you need major components from another game to play (so all the ASL expansions are, indeed, expansions) but it's not an expansion if it can be played alone (even if you can combine it with another game). So Nuclear Escalation is separate from Nuclear War, Here Come the Rebels is separate from Roads to Gettysburg, Munchkin Bites, Munchkin Fu, Star Munchkin and Munchkin are all separate games (but Munckin Blender is not).
 
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Emile de Maat
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Then not all of the ASL "expansions" are expansions. The Starter Kits are stand-alone games...

That's fine; it's not my goal to remove as many ASL items from the list All in all, I find that dakarp's guideline that a game is a "base game" when you can play it stand-alone quite clear.
Biggest problem I see is with CCGs; I can play Magic: Ice Ages without any card from the Magic base set...
 
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Chris Shaffer
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If the only thing you are talking about is manipulating the ranking lists, then I withdraw any objections. I don't care one whit about the rankings - they mean nothing to me and I never look at them.
 
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