I spoke with the following group to find out more about how the hardcore Arena system will function as well as how the ranking system will determine comparative skill between players.

• Luke Timmins - Lead Multiplayer/UI Engineer
• Tyson Green - Systems Designer

Luke Timmins: We want to take a new stab at the scoring system and come up with a 'pure scoring system'. We thought a lot about the different pros and cons of [our previous system. We didn't like that it penalized the best player on the losing team. What we came up with was the Arena. It has a different vibe. It is a hardcore, Slayer-only [area]. You are going to be given a rating compared to the rest of the population broken up into divisions.

It's a season-based model, which [helps prevent account smurfing]. If you played a bunch in Halo 3, you'd hit around 40 [skill] and all of a sudden you're number isn't going up. Players would say, 'I guess I'm done. Do I make a second account?' The season model does some really cool things. At the end of the season, it goes on the back of your 'baseball card' and the next season begins fresh.

Tyson Green: With the Arena rating system, we're trying to say, 'Here are the things we value and our players value in-game.' You get a higher rating by doing things that good players do: working with your teammates, getting kills and assists, and not dying a lot. You're playing Slayer, so if you die, you're giving [the enemy team] a point. Say you have two guys, one has a kill:death spread of 10 and the other has a spread of 2. Even if the guy with 2 scored a few more kills - the guy with the higher spread will get a better rating. The game is saying, 'You did the better job. You were playing the game better and working with your team better. This is what contributes to your overall rating.'

Luke Timmins: If you look at the different layers of Halo players, there are guys that really understand kills, deaths, assists, working as a team, and all the stuff that [will go into this rating]. We basically wanted to bubble that up, pull it out, and put it on the table: this is what Slayer is. We can now tell you, 'You did well', if you actually play well.

If Tyson wants to play with his little brother, who isn't that good, Tyson can play with him. His brother might suck, but Tyson might be really good. He can go in and get a good rating game after game after game. This is something that our Halo 3 model did not do well.

Play with who you want. You're going to get scored individually.

Tyson Green: Our seasons are probably going to line-up with calendar months. For the September 2010, you're going for the best division you can by the end of that season. To get there, you get rated on individual days. For example, if you need to get a rating on 5 days to get a rating for the season, that means on 5 separate days, you need to play a couple of games each night.

The day rating is based on the best selection of a night's games. You'll never have a situation [where one bad game] brings your rating down. It happens behind the scenes for matchmaking purposes and season standings, but every day, it's all about your best performances on that day.

Luke Timmins: We can tell people, 'Play this many games a day for this many days and you will be rated in the season.' You will know the minimum amount of participation you need for the Arena for that season. We didn't want this be like, 'play 30,000 games'. It's not a grind.

Tyson Green: There's a certain minimum bar that you have to meet to enter. At the end of the day, your day rating gives you your performance against your peers. At the end of the season, the division that you're assigned to tells you who your peers were.

Luke Timmins: You can't just play the best four games of your life and end up with the highest rank in the season.

[The Arena] is a special spot that we can carve out for our hardcore players. You're not going to go in there and find, I'm not going to bash some of our less-hardcore gametypes, but you're not going to find Rocket Race in there. There are people that should play in the Arena and people that wouldn't be happy playing in the Arena, but we have this whole other area just for them.

Shack: How much of this taking cues from real-time strategy games or something like World of Warcraft's Arena?

Luke Timmins: What is the game you mentioned? World of what?

Tyson Green: Shut up (laughs). There's definitely bits of it in there. We've looked at things like chess and the ELO system and quarterback ratings from the NFL. There real inspiration came from this notion of, 'can we take someone's performance and distill it down into a number?' People can compare numbers with each other and have it be meaningful in the same way NFL quarterbacks are compared with the QB rating.

We looked at the way seasons worked in World of Warcraft arenas, but we think those seasons are too long [for us]. They are based around [Blizzard's] content cycle and not on what would be an optimal season duration. There are bits and pieces taken from other places.

Shack: Can you move divisions within the same season?

Luke Timmins: Yup! Up and down.

Shack: Is this division and ranking tech Reach specific or did you work with Microsoft to build this into Live?

Tyson Green: It's Reach specific. We're still using TrueSkill to actually build matches, but we're using it in a less-constrained version than Halo 3, so it works faster and it works better. I think [Reach] is one of the first titles to use TrueSkill properly.

Luke Timmins: With Halo 3, to get what we wanted out of TrueSkill, we had to abuse it in various ways. A big part of what we want to do is let TrueSkill do what it's amazing at, which is giving you meaningful skill numbers that we can use to match you. On top of that, we wanted this additional layer that is more meaningful to users.

There were a lot of things that sucked in Halo 3 for users. Once you got dialed in, your skill wouldn't change. We were promising users the number would go up and all of a sudden it doesn't. Players felt like they were done.

Stay tuned for more on Halo: Reach including information about combing Ranked and Social playlists into one straight from the developers.