WoW Mythbusters: LFD Gear Matching

A second rumor I’ve heard about the LFD system is that it does match-making based on the gear of players.  Under-geared players will tend to be matched with well-geared players, and vice-versa.  The dungeon finder will therefore create groups that should be able to clear, even for fresh 80s.

TL;DR:  This appears to be true – LFD involves a matchmaking system that places less-geared players into well-geared groups.

Second Approach: Group Gear Levels

Suppose, for a moment, that the set of players I’ve grouped with is representative of the population of WoW players. (Yet, somehow, nobody got booted from these runs / acted like a jerk / was a complete and total idiot… so given whats been blogged about, this might be a heroic assumption.)

If the que was going to randomly assign groups, it’d pick 1 tank, 1 healer, and 3 dps out of the assortment of players I’ve been matched with.    On this random assignment theory, LFD would produce groups that were both under and overgeared – which I’m going to approximate by looking at average gear scores for each group.

LFD, if it is matching groups based on gear, should distort this distribution. I’m guessing that Blizzard is mostly concerned with avoiding “wipefest” groups – and so ensures that freshly-leveled 80s aren’t placed together into heroics.  I’d expect this would yield under-dispersion: fewer groups with worse gear.  (This would also alter the distribution of average and higher-geared groups, but the effects are more ambiguous).

I’ve simulated the distribution of average gearscores given the players I’ve observed over ~100 runs, and compared it to the actual data.  The plot on the right graphs the average gearscore each group I’ve encountered in LFD, by type of instance.  The plot on the left shows the estimated average gearscore of each group, had groups been randomly generated.

The LFD system is preventing under-geared groups from forming:  my model random group generator produces some groups with abysmal gearscores.   Some groups would have an average gearscore of under 3k.   I never observed any groups with this level of gear, even on my worst-geared characters.  (Note:  its still entirely possible to clear heroics with this gear – just not at the pace generally expected nowadays.)

By preventing under-geared groups from forming, LFD produces fewer all-star groups than would be expected.  The average average group score (ha – confusing or what?) is slightly lower for LFD than expected.  To see this – look at the peaks of each distribution.  For the random groups – on the left – there are many more groups around the 5k average.  The LFD peak is slightly lower – around 4.8k.  LFD is also producing more groups with 4-4.5k averages than the random generator model.  Why?  Because its raising up the otherwise-undergeared groups to this level.

These effects occur regardless of heroic ‘type’.  (Some players que specifically into ICC-5 and ToC-5, for upgrades via drops, so these instances should have distorted distributions – but the effect occurs, regardless of heroic type.)

What does this mean?  Its unlikely that LFD is producing groups randomly.  Instead, its newbie-friendly, ensuring that the worst geared players are matched with players with better gear.


PS:  Admittedly, this would be easier to do with data on the overall distribution of gearscores, the distribution of tanks, etc.  But please stop me before I write a webcrawler.


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