http://forum-console.worldoftanks.com/index.php?/topic/20198-matchmaking-mechanism-explained/ "According to another aspect, the matchmaking server may store a win/loss percentage for each user (or vehicle) at a given battle level. As the player's win/loss ratio decreases, the player becomes more likely to be placed in battles having battle levels at the lower end of the allowable range, whereas as the player's win/loss ration increases, the player becomes more likely to be placed in battles having battle levels at the upper end of the allowable range. Thus, when a player has been repeatedly put into too many difficult battles, the balancing is done in favor of easier battle sessions, thereby encouraging the player by providing an easier game environment. Similarly, when the player has been repeatedly put into too many easy battles, the balancing is done in favor of harder battle sessions, thereby keeping the player challenged instead of letting the player become bored with easy games."