Inspired in part by msaari's resurrection of the correlation calculator ( http://www.boardgamegeek.com/thread/130097/page/1), I thought it would be neat to be able to easily calculate collection overlap as well as identify the rarest portions of that overlap. So, using the XML API (with one small extension, which will be generally available soon), I made a tool that does just that:

http://boardgamestuff.com/cgi/bggcolloverlap

The "score" is simply an average of the percentage overlaps relative to each collection. I like this number in that it captures what I subjectively think of as "collection similarity".

For me, a few examples:


User Games in common "Score" Rarest overlap
Aldie 333 43 Spinball
Kaelistus 130 38 Pagoda
Octavian 91 35 Techno Witches
TomVasel 258 33 Moby Pick
msaari 65 27 Klondike

Ooh, nice! This is pretty cool (and I'm curious what the small extension is about...).

Stop it! I'm running out of quickbar!

My examples:
User Games in common "Score" Rarest overlap
mkgray................154................24.5......Camelot
Aldie.................209................26........Infinity (Cool!)
TomVasel..............203................25.5......Weapons & Warriors
DWTripp...............63.................26........Fury of the Clansmen
ynnen.................173................29........Red Hot Yott
tinytimidfluffybunny 59.................33........Streets of Fire -ASL
Thommy8...............53.................33........Trivial Pursuit #5
Sky Knight X..........80.................26........Battlecards: World Conflict

It's an interesting tool. I have yet to find anyone above the 33 I have with Thommy8.

Games in the /xmlapi/collection view now have an "owners" attribute which says how many people have listed that game as owned. It lets you see, for example, which games you have that are the rarest among the BGG community.

Eg, I'm the only one who lists "Hat In The Ring" and one of two who owns "Stapelei" and "Rutschpartie mit Winnie the Pooh".

Me.

Sorry, Scott (and Bas)....

Overlap score: 40

EDIT: WOOPS never mind... i was reading the stats wrong...

It looks like /xmlapi/game/123?stats=1 also now returns an owned tag? Or was it returning it before and I missed it?

Oh, yeah, that too. I forgot I put that in.

Nice!!

How about a "wishers" attribute too, giving the total number of people that have the game in their wishlists? Might be something fun about comparing the numbers of owners and wishers across several games... or not.