Just before 'Halo 4' released last year, 343 Industries made a last-second announcement revealing the game's Competitive Skill Rank (CSR) system. Unfortunately, it wasn't in the game at launch. Like in "Halo 2" or "Halo 3" players stats and individual game performances, upon final release of CSR, will be tracked and used to create a ranking from one to 50 on a per-playlist basis. We now know that system is coming to "Halo 4" sometime in April, five months after the game's release.
IGN spoke with 343 Industries Jessica "BS Angel" Shea, who provides content for Halo Waypoint, at PAX East, who reveals the planned "early April" release for the CSR system. The CSR update is not related to the upcoming Title Update or recently released free Forge map and players can expect their statistics to reset in conjunction with integration of CSR. Much like previous "Halo" games, CSR will, ideally, allow comparatively skilled players in any given playlist, from Infinity Slayer to Team Snipers. Obviously that's going to take a little while to work as expected out as players build up their rankings from the statistic reset.
IGN also reports, "343i did say that they will serve overall resets semi-frequently. They believe resetting things from time to time will motivate people to keep playing and will continually give people new goals." Additionally, there should be some sort of optional prestige-reset function at play, but 343 Industries didn't say much else on the detail. It's unclear what common stat-resets would do to serve the CSR system, but "Halo 4" devotees can expect a "semi-frequent" struggle to maintain their rankings.