Thursday, July 14, 2011
World of Tanks matchmaking interview
Today on Tobold’s MMORPG Blog we have something special: An interview with Chris Keeling, Military Advisor at Wargaming.net, developers of World of Tanks. Chris, I understand you are a military man, you have fought in Iraq, and then went on to work on various war games. What exactly is your position at Wargaming.net today?
Chris: I serve in a variety of roles – which is unusual for me because I am normally a writer or designer on a development team. I had the privilege of working with Wargaming.net on their previous World War II RTS, Order of War, acting as the game writer and also as their advisor on military and historical topics, American culture, and the English language, and have gone on to serve in similar capacities on World of Tanks. I am also involved with some of the communities that relate well with World of Tanks, including veterans, historians, tank modelers, and reenactors, and use my contacts there to evangelize the game in those areas.
Tobold: The specific subject I would like to talk about with you is matchmaking in World of Tanks. What can you tell us about the design philosophy behind World of Tank’s matchmaking algorithm?
Chris: For version 0.6.5, you can find the chart depicting the matchmaking system here. Note that this has changed from release to release as we have tweaked the balance due to player feedback and data we have collected from literally millions of battles. Part of the dichotomy between the way matchmaking works and the perception of unfair battles lies with the way we consider tanks to be balanced; we take the long view, of cost to maintain compared to average revenue (both experience and credits). Over the course of a player’s “career” from Tier I to Tier X, each vehicle at each Tier is balanced against other vehicles in that Tier in terms of their ability to generate income. Indeed, they are fairly and accurately balanced in that regard. However, as we have seen, the players expect a different kind of balance, and one which appears more reasonable on the surface. The players just want their tanks to be able to kill other tanks. As our internal data shows, even this is actually very well balanced across the system at each Tier (except for a few that slipped through, like the premium Löwe and Hotchkiss).
Tobold: While being extremely fast in getting you into a battle, World of Tanks accomplishes this by having a wide spread of different tank tiers in the same battle. Many players feel that getting paired against a tank 4 tiers above them (in some cases even more) results in them not even having a chance to contribute anything meaningful to the battle, as their guns are unable to penetrate the high-level enemies’ armor. Some reviewers of World of Tanks agree, I’ve seen matchmaking seen listed as weak point in several reviews. Would you say that matchmaking is something you are happy with in its current state, or is that something Wargaming.net is working on to improve?
Chris: We are always seeking to improve the game, in every aspect of its development and presentation. We know it can be frustrating to get thrown into a battle where you’re the lowest tank by several tiers, so matchmaking improvements are high on our radar. But we also know that players don’t just want to be killed once for each enemy tank they destroy, they want to dominate the battlefield. For true balance, this means that every time a player gets 5 kills, they should end five battles wrecked without having eliminated any enemy vehicles. Over the course of hundreds and thousands of battles, this does tend to average out, which means, sticking to the example, each player having five unenjoyable losses for every 5-kill streak of victory. Balancing this out so each player doesn’t have to suffer a miserable experience several times over for each impressive success is a lot more complex than just balancing armor and penetration values.
Tobold: From my experience with various online games the problem of matchmaking is to find the right balance between finding the perfect match, and doing so fast. But it appears to me that there is room on the time scale; playing at prime time means getting into a battle within seconds in World of Tanks at the moment. So how about a simple solution of reducing the matchmaking “spread” by one tier, so players will at worst be paired against tanks 3 levels above them? Have you considered matchmaking algorithms which take current server population into account? When there are lots of players, battles would have a narrower spread of tiers, but during off times the spread would widen to avoid long queues.
Chris: We’re considering a lot of things, and there have been some good suggestions from the community, including separate queues for “Quick Battle” (loose matchmaking, kind of like what we have now) and “Balanced Battle” (waiting for up to several minutes for a battle that has less Tier spread), reducing the spread of Tiers to no more than two above and two below (similar to your own suggestion), and possibly even allowing Premium players to start battles with specific parameters, such as Tier limits, vehicle type restrictions, and map selections (similar to the current Practice battles, but without private invitations and counting fully for experience and credits). We don’t know what, if any, changes we will make, but rest assured we are looking into all of these options carefully. And as far as the server population goes, the 150,000 players typically found on the Russian servers at any given moment ensure a quick battle with much less deviation than we get here – so if you can get about 135,000 of your closest friends to play on the NA servers, I think we can guarantee better matchmaking!
Tobold: Thank you for this interview, Chris. Is there anything else you would like to share?
Chris: Thank you for the opportunity to talk about the game! I love this game and I play it like everyone else, looking forward to the first x2 victory of the day, the x5 treats and other events, and I suffer through the same matchmaking, spotting, and lag issues as any other player. If you see me in chat or in the game, feel free to say hi! In-game, my nick is ChrisK. And please don’t shoot my son, ChrisKjr – he’s only 7, but he enjoys the game too!