In a new feature, MMO publisher Innova's head of analytics, Dmitry Nozhnin, writes that while it's harder

to track when veteran players are going to quit your game, it's possible -- and worth it. "For new players, defining churn was dead simple -- they just leave the game after a couple of minutes or hours.

The science of predicting MMO player churn

"For new players, defining churn was dead simple -- they just leave the game after a couple of minutes or hours. That's it. The last day of play was clearly defined, and data mining models on such churn factors were already well established," writes Nozhnin.

The question is much more confusing when it comes to veterans, though.

"Manual data investigation revealed that majority of churners have a 'long tail' of play days -- those occasional activity days during several weeks, or even months... They effectively stopped actively playing the game, but still log in from time to time."

These players may jump in to check auctions, chat with friends, or even pass their account along to guildmates for use -- but if you detect their behavior that late, they're already gone.

It turns out, however, that it's simpler than you'd expect to figure out when those players will quit.

"Most fascinating is the fact that final data mining models with best precision were entirely based on derivatives and calculations of only two metrics -- days of activity and daily playtime!" writes Nozhnin.

The full feature, in which he goes into his methodology for creating the analytics-- is live now on Gamasutra.