[url=http://forums.bungie.org/halo/archive35.pl?read=1054300]Taken from a post about the death of the Halo Black Market with the invention of Arena.[/url] [quote]Halo 2 did not use Trueskill. It used an ELO based linear rating system. It's strength was that since it was ELO and linear, Bungie could mangle the numbers into displaying as progress bars. Put enough work in, and you could inch your ELO rating upwards into the next boundary, indicated by 1-50 ranks. Of course, there were many downsides, some massive to this setup: 1) Instead of treating it as an indicator of your relative skill to get you into close games, people treated it like their World of Warcraft account, a level to grind and earn that they 'deserved', because everyone figured that if you put enough games in, you'd reach 50 as an eventuality, since they confused the bar-display of the ranks on Bungie.net as experience bars instead of a bounds indicator. I often heard people refer to a gamertag as "their 25" and that they were going to "get on their 32 tonight", like the gamertags were characters they created instead of themselves. 2) Ranks above 36-38 were basically not achievable by normal humans with jobs and a life. Both physically and mathematically. If anyone remembers BEFORE the big Halo 2 patch, 25 was a high rank. Bungie even had an interview on their front page with the "highest ranked Rumble Pit player", who was an 18. Now think about that. What was the point of having 50 distinct ranks if 25 of them went unused? This resulted in MASSIVE rank compression and less skilled players being forced to play much better skilled players because in this system, a 15 could be matched against a 25, which was basically the equivalent of a 20 being able to be matched against a 50 in a Halo 3 playlist set to 'strict skill level'. 3) The big patch didn't do much to alleviate this, as all it did was add about 10 ranks to the top end. The high 30s and 40-50 were basically only gotten by boosting and cheating. about 19 out of 20 games against someone with a moon or other graphical rank were modded games. The others were simply people who had boosted rank. You think dropping a single rank in Halo 3 was annoying from a single game? Try playing 50 games to move up from 43 to 44 in Halo 2, and then being dropped down to a 42.5 from a single loss, due to the math. Losing to anybody but someone of the same or higher rank was deadly. 4) In ELO, it's possible to lose rank for winning. It's happened in chess many times, and it even happened to me in Halo 2. I earned a 32-33 in the Ranked BTB playlist before the big wipe - I had about 700 games completed of BTB at that point. One night, we had an amazing run with a full party of 8 where people in the party went from 22 to 27-28. I was ranked down to 29-28 from WINNING because all the people that were left were no higher than rank 15-17. I thought it was hilarious myself, but someone hardcore about rank would have been livid. But this is a result of ELO - it is designed to punish someone for playing someone far below their rank, and to stay near people of their own rank. Of course, that is counter productive to 5) Halo 2's ranking system was also used in matchmaking, in both ranked and social (guests allowed) playlists. Since the rating system encouraged you to play people near their ranks, you'd end up with massive gaps of rank. Since there were massive gaps of rank, when people stopped playing the game it would result in epic search times. [url=http://upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Standard_deviation_diagram.svg/500px-Standard_deviation_diagram.svg.png]In a pure Trueskill system, the population's skill distribution looks like this for all playlists combined in optimal conditions: [/url] [url=http://i.imgur.com/tuHxH.png]In Halo 2's ELO, it was more like this: [/url] Everyone was clumped together into little islands of skill. When population dropped due to competing games and the launch of the Xbox 360, this islands could disappear practically overnight, causing a chain reaction of people moving to other playlists or just not playing Halo 2 anymore due to search times. The only way to fix this was, of course, to reset the ranks. While I personally didn't mind, people who had marched to a 50 somehow legitimately were screwed. They had to do this 3 times. Once for the Big Update, second time was in mid-2006 when they issued a big anti-cheat patch, and the last one was when the Blastacular Map Pack came out. The first one was sort of a given since the game had dramatically changed. The others were to simply to keep matchmaking working. But now I'm starting to drift off my own topic, which was the Halo black market of boosting. In Halo 2, people dealt in Live gold time. If you had enough 2 months, you could get a guy to mod or standby/bridge you to wins. This cheating was RAMPANT. Not only did you have to deal with the endless amounts of players with the bomb or last flag going out of bounds, but snipers super bouncing to the top of maps, you had to deal with modders who would just make your team spawn in midair and squeeze out a game in a minute. Or the more clever ones that would bridge themselves host (another topic entirely) and then ban your IP from their router, kicking you out of the game. By the time Halo 2's 1.5 patch arrived that killed modding and bridging, it was too late. Most everyone was on Halo 3. To this day, nobody will ever have an idea of how Halo 2's multiplayer should have actually been, because 99% of it wasn't spent playing Halo, but rather a metagame of who knew more exploits such as BXR and superbouncing and cheats.[/quote] TLDR: -People treated, and still treat, ranks like a WoW level bar. -The requirement for top ranks was insane. Lead to lots of rank compression. -Once you started getting near the top, you could derank huge amounts for single losses -You could derank from a win. -The system created islands of players. When people stopped playing, search times grew large, quickly. This was the reason for the several rank resets in H2.