Thursday, May 5, 2011

Causation, correlation, and World of Warcraft, part 2 of 3

This post examines the phenomenon of data mining as applied to a real world example that anyone can observe.

Let me start by stating that I have seen the practice of data mining and the obscurity of causation versus correlation (all of which is explained in the previous post on this series) occur over and over again in real businesses in which I've worked.  I don't want to discuss the inner workings of those businesses since I had a privileged view on them, so instead I'll pull an example from a popular online game that anyone can see, World of Warcraft (WOW).

A couple of caveats first:  I am not and have never been an insider at Blizzard Entertainment or for the World of Warcraft products.  I know no such insiders.  I also am not a WOW player, although I know people who are.  I'm building this example on something I (or anyone) can observe and my own hypothesis about why Blizzard designed its product that way.  I may be flat-out wrong.  However, that's not important.  Even if this hypothesis is completely incorrect, we can still use it to illustrate how data mining affects business decisions and the potential fallacy therein.

That said, let's start with observable facts.  World of Warcraft is what we call a leveler, a game in which one has a character (or multiple characters - an important point here) in which one can achieve goals an increase the character's powers or abilities, which in general terms can be called leveling up.  Part of the way one levels up in WOW is by gaining points of experience, which are rewarded for defeating enemies or accomplishing other goals.  Now, there are various mechanics in the game by which characters can gain experience faster than they otherwise would to accomplish the same tasks.  For example, there's a mechanic whereby a player can meet up with random other players and mutually go after tasks ("run dungeons") together, and the players will gain more experience for the tasks than if they had accomplished them otherwise.

My first hypothesis is that the folks at Blizzard have created these rich experience earning environments on purpose to encourage certain behaviors in players, behaviors they deem good for the overall WOW ecosystem or simply for their own bottom line.  (Again, let me emphasize that these are my own speculations and that proving them correct or incorrect is not important to the lessons we can learn from this exercise.)  In the above example, I imagine that it's good for the WOW community to encourage players to meet new people and this this mechanism causes that to happen.

That's an easy one.  But let's look at another rich experience earning mechanism that might be a little less obvious.  One phenomenon in WOW is that if you leave a character dormant, the ability to earn experience actually increases.  How it works is that if your character goes unused for some period of time (what they call resting in the game), a limited opportunity will occur to earn experience at double the ordinary rate.  The longer a character rests, the larger the double-earning opportunity, up to a maximum number of experience points.

So we have a mechanism - deliberately built into the product - that encourages players to use characters they have not used recently.  Now, why would Blizzard do that?  A few ideas occur to me.

It's possible that Blizzard Entertainment wants you to do other things besides play World of Warcraft.  The company wants you to go outside and enjoy the fresh air, maybe take in a movie or spend some time with friends.  The company wants to ensure that you keep your WOW consumption to a minimum so that you live a healthy, balanced life, and this mechanism encourages that.

It's possible, I suppose, but that's not the way companies typically think.  Let's look for a more likely explanation.

My more likely explanation is that Blizzard wants to encourage players to maintain multiple, active characters rather than just focusing on one or two.  From what I've seen, WOWers tend to have lots and lots of characters.  An account may maintain up to ten characters, and people seem to push that limit.  Now, under those circumstances there are a few different ways to play the game.  One is to focus in on one or a few favorite characters and play them a lot, touching the others infrequently or not at all.  The mechanism described above encourages players to increase the number of active characters they're engaged with on a regular basis.  The longer a character sits unused, the greater the incentive to pick it up and play it again.  So Blizzard is using the carrot of increased experience points to increase the average number of active characters each player has.

That feels like data mining to me.  My guess is that the folks at Blizzard have looked into the statistics behind their user base in pretty fine detail.  After all, it's a big business with twelve million users logging more than one billion play hours a year.  I'm sure they've analyzed their user base to the nth degree.  I further guess that someone at Blizzard has determined that it's good for them if the average number of active characters per player goes up.  Maybe those players with more active characters renew their subscriptions at a greater rate.  Maybe players with more active characters are also more active in recruiting new players to the game.  Maybe players with more active characters are also more active in other parts of the WOW world and help create a richer experience for everyone else.  Maybe it's all of the above.

Either way, if Blizzard really did mine its customer data and find these correlations, it appears that the product team then chose to encourage players to have a large number of active characters on the assumption that increasing this overall average would improve these other metrics, the ones they really care about.  It could be that these mechanisms indeed have had that effect.

It could be.

But not necessarily.  Join me next time for part 3, in which we'll scrutinize this reasoning in light of the difference between causation and correlation.

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