Short version: Microsoft's philosophy is correct (or is it...?), our ranking system should only consider wins and losses and should maximize close matches using TrueSkill, or a close implementation.

But Pardo was not quite on board. Such a ranking system is harsh and while hardcores are ok with it, regular people just get crushed and discouraged. They don't get to see any real progress, he said.

Yes that's true, I responded. And yet competitive games flourish and top the sales charts. We shouldn't ruin our ranking system with some experience point system to help people's egos because that will necessarily make the matchmaking system worse. No matter what anyone claims to want, they will be happier with close matches as those are memorable and intense, and that trumps anything that deviates from the TrueSkill philosophy, I said.

Pardo said that he really wanted what he wanted though, and if he's asking for a system that is more friendly to non-hardcores, then I should be able to come up with one. "If someone put a gun to your head and said to give some sort of incentive to keep people going in a ranking system, what would you do?" Yes, fair enough. If he's asking a question, I should be able to provide an answer. But I still thought the question was more like, "should we ruin the perfect matchmaking a little, a medium amount, or a lot?" while I was thinking, "let's not ruin it at all!"

Later, I presented a system that used a TrueSkill-like number for matchmaking behind the scenes, and that did not deviate by allowing any nonsense stats to affect it. But the UI would prominently display 1 main experience level stat (not the skill-based stat) and 2 other stats that were destined to go up over time as well. (Think "headshots", though it wasn't exactly that. Stats that naturally increase over time.) These secondary stats were dressed up a bit in the form of levels, too, so you basically had three meters going up. The fourth stat, the REAL one, was also displayed (and used for matchmaking!) but it was displayed less prominently. Players had various progress bars to level up, but still perfect matchmaking.

Pardo thought I at least gave it a try, but that I had not tried hard enough. He said "we don't need hyper-accurate matchmaking out of a ranking system. That's not its primary function." This is around the time when Street Fighter HD Remix started, so I did not get the chance to submit a revised system.

What did he mean by that last statement though? Isn't "hyper-accurate matchmaking" exactly the thing we do want from a matchmaking system? Years later I’m willing to say, “maybe not.” It could be a good trade-off to have merely “very good” matchmaking if in exchange for losing “hyper-accuracy” we also gain some fun or keep people playing when they otherwise would have given up. Microsoft’s premise was that hyper-accuracy gives you the most fun possible, but perhaps that premise is not strictly true. Maybe there is a way to add fun without losing much at all in the way of perfect matchmaking. Starcraft 2’s bonus point pool system could be that way.

Starcraft 2’s Bonus Point Pools

The bonus point system is similar to the “rest” system from World of Wacraft. Players accumulate a pool of bonus points over time, capped at some maximum. In World of Warcraft, the function is to give you double the experience points each time you kill a monster, until your bonus points run out. In Starcraft 2 the function is to give you double the *ranking points* each time you get a win, until your bonus points run out. For example, if you were facing a stronger opponent such that winning gives you 10 points and losing would subtract 5 points, then winning would actually give you 20 points. 10 points would drain out of your bonus pool and go into your ranking points (to match the 10 points you’d normally get for winning here). If you lose, you would lose 5 points as usual with no further adjustment.

What is the effect of this system? Some people claim it rewards those who play a lot, but this is looking at it the wrong way. Those people would claim that play-a-lot guy gets more ranking points overall because he uses up all his bonus points all the time, while a play-a-little guy would not play enough to use them up, so he’d get fewer points overall for his wins. True, but missing the point.

The actual play-a-lot guy will play way more than his bonus point pool can hold. Most of his matches will be played without any bonus because the maximum size of the bonus pool must be fairly low for this system to even make sense. Meanwhile play-a-little guy will play most or all of his matches with boosts from these bonus points. So if anything, play-a-little guy benefits. (Though the play-hardly-at-all guy is disadvantaged because he doesn’t use up all those bonus points.) But even THAT isn’t the point.

I think there are two real points to this system. First, it gives you an incentive to play when you otherwise wouldn’t. If you haven’t played in a few days or a week or whatever, you will think “hmm, I could play right now and get the benefit of those bonus points!” And if you wait until the points reach their maximum (in World of Warcraft that’s two weeks, but unknown as of this writing in Starcraft 2), then you’ll have another reason to play: that you would be “wasting” bonus points by not playing. If you just played enough to use up some of the bonus points, you’d be able to keep accumulating more for later. Yes it’s a psychological trick, but at least it gets more people active, which basically helps everyone involved (more opponents).

The second real point hits at something Pardo was originally asking me for: a way to have at least some feeling of progress in the harsh world where actual progress is damn hard. Imagine that Alice, Bob, and Charlie all have 1100 ranking points and that they are all of equal skill, so any matches between them will have a 50-50 chance of going either way. Alice doesn’t play for a while (but her skills don’t decline). Bob and Charlie play each other, and also play even more players of the same ranking/skill. After a while, Alice will still be at 1100 (she didn’t even play). Bob and Charlie will have a HIGHER number of ranking points though, due to the bonus pool. Even if they have even records of 30 wins, 30 losses against each other, they are gaining more points than they are losing because bonus points are added for wins, but there’s no extra penalty for losing. They have the feeling of progress here, even if it’s illusory.

Does this screw up the actual rankings? Well, Bob and Charlie might find themselves at 1300 ranking points (I’m just making these numbers up), so you could say their ranking is inflated. But...not really, because all the other people of their same skill out there have inflated rankings by the same amount. Really, it just stretched the scale out. It’s true that Alice will have bad matchmaking when she decides to play again though. Her rating is 1100, but because of the point inflation that’s gone on, she really “deserves” a higher rating now. That will correct itself pretty quickly though, it just means she’ll have a few matches that are easier than expected when she returns. This is the imperfection in matchmaking that we have to accept if we want the good features of: 1) more people tend to play more, and 2) ego boosts even when you go even against evenly matched opponents.

Also consider that this ego boost is not changing your ranking against a list of specific competitors. If you’re the 1000th best player, you’ll still be that, it’s just that everyone’s points are creeping higher over time. (There’s a reset every season, so it won’t go infinite.) Since your REAL rank as 1000th best player is intact without too much monkeying, it seems ok that the underlying stat increase, as a psychological motivator. We still know who is actually better, so who really cares if everyone’s underlying stat is one that goes up over time or not? Really only your ego cares, so we might as well throw you a bone.

To put it another way, I was thinking about how I have not played Street Fighter HD Remix online in the last two weeks. If I had some bonus pool points waiting for me there, would I have? Probably yes, as dumb as that is. And yet if that made me and thousands of other people play a bit more, it helps the whole scene, so why not.

Focus on Ranked Matches

Microsoft has a clear philosophy on this one too: sometimes people want to be ranked because they are seeking out competition and a way to measure themselves against others, but sometimes people want to avoid all that and play without any fear of shame or losing. Xbox games must have both a ranked mode and an unranked mode (badly named “player matches”). In ranked mode, developers can show any kind of stats to the player they want, while in unranked matches, they are supposed to hide these stats as much as possible. This makes total sense to me, as even I don’t want some record of how bad I am at some game I’m just messing around with. And sometimes I don’t want a win/loss record shoved in my face either.

There’s a tension though, and it goes back to matchmaking. We really want you to play ranked matches a lot so that we can accurately determine your skill level and give you close matches. In Kongai, a card game I designed, we did what some other games do by just renaming the modes. The modes used to be called Ranked and Unranked, but now the ranked match is just called Play Game. This shifts the perception of which one is the one you’re supposed to play. While Ranked sounds ominous and serious, Play Game sounds like it’s for everyone.

Starcraft 2 takes a similar approach here. The default mode is ranked, and it’s not named some scary thing, it’s just presented as the normal way to play the game. The screen where you get into a game devotes only a small space in the corner to creating / joining a Custom Game, which is the equivalent of unranked.

The notion that you’re always playing ranked could turn people off, but it does help matchmaking, like I said. Overall I’m weakly in favor of it.

Divisions

Followup: Some people have said that the matchmaking stat is not affected by the bonus pool points, and that the bonus pool points are only used for display purposes, like where you appear in your 100 man division. This is not the impression I got from Blizzard's statements, but that claim could be correct. It's also possible the answer to that changed at some point, as who knows what adjustments went on during the beta. If the claim is true, the system matches you by a different criteria than it actually rates you. I don't really know what to think of that.

More information here that the bonus pool points do not affect the "real" underlying stat used for matchmaking, only the ("fake"?) displayed ranking in your division.