We were clipping players to +/- 4.0 MMR

This would be 4 standard deviations IF the mean was 0 and the standard deviation 1.0

This is not the case in many playlists. For example, FFA has a mean AND standard deviation of around 2.0 each. So FFA was being clipped to only 1.0 standard deviations on the top (hence 1200 CSR).

We have changed it to clip 4 standard deviations from the mean, by playlist. So, using FFA as an example again, it will clip to 2.0 +/- 8.0 or [-6, 8].

Social still expands for only 40 seconds like always, and then gives up on skill

But we added a max skill gap equal to half the distribution (4 standard deviations)

In case you hadn’t read the blog , the next season starts this Thursday, July 6th. This will include changes to Doubles, FFA, and the return of Ranked Snipers.In addition, here are some more changes you can expect to matchmaking.As discussed in the past, the way Halo 5 chooses which map and mode to play is by randomly choosing a map-mode combination from a list of the possible ones for that playlist, making sure to not choose an entry that anyone in the match played in their last match.The HCS playlist has exactly one entry for every official HCS map-mode combination. Having only one entry per combo means you will pretty much never get the same thing twice if you stay in the hopper.However, since there are more Slayer combinations than any other, it also means playing Slayer maps almost half of the time.We’ve heard your feedback that there’s a bit too much Slayer, so we are going to add duplicates of CTF and Stronghold combos to balance out the proportions, starting with the new Season this Thursday.This does reintroduce the possibility of getting the same map-mode combination more than once in a row but will hopefully be preferable than lots ‘o Slayer.In the future, we will add the ability to weight playlist combinations, so they appear in even proportions without duplications.The skill rating system (MMR) is supposed to clip everyone’s MMRs at the beginning of each season. We do this to trim off inflated player skills. We fixed an issue before last season that was preventing this clipping from happening.Then, we discovered that the clipping was too aggressive in many playlists, making it so higher-skilled players had unusually large gaps between their MMR and CSR values, especially in FFA where players were starting at 1200 and having to climb up to 1800 (+600) just to get champ.We have tuned that correctly for the new season coming, so the starting gaps for higher-skilled players will be more reasonable.For those curious about the details:Last week I explained that we had changed the way SWAT and FFA expand their skill ranges in order to guarantee every player can get in a match within the 5 minute max wait time.This week, we made a change to Social and Warzone matchmaking. In the past, Social matchmaking had been the same as Ranked, but with no enforced maximum skill gap. This meant that a “Bronze” player could easily get into a match with an Onyx player.Gaps of that size create matches that are a joke for the Onyx player, and the Bronze player doesn’t even feel like they can play.Also, gaps that large make it so if you are the Onyx player, we must put all the Bronze players on your team to balance the match fairly against the other players who are usually Gold / Plat.This can create undo stress on the Onyx players who will have to super carry their teams to win, making Social a bit sweaty if they want to win matches.To alleviate this, we made this change:So after “giving up” on skill, Social will still have at least a safety net.This is still a huge gap, but roughly half what we allowed before. This means top players won’t see worse than high-Gold / Platinum players in their matches. Bottom players usually won’t see players better than those Gold / Plat ones.We did the same thing in Warzone as well. We also kept Warzone’s expansion time to 30 seconds before it gives up on skill and allows the new, large, max gap.The new expansion rules we tried on SWAT and FFA have been successful overall. The players who were no longer able to even play those formats are now getting matches guaranteed in under 5 minutes.This also has the side benefit of making it easier for legitimate teams to catch up with Smurf teams because they can get into matches without needing Smurfs on their teams. The gap is closing a bit there.We added these same rules to Doubles as well during the past week because that was another area higher-skilled players were struggling to be able to play the game at all.With the new season, we will be incorporating those tunings into all Ranked playlists. This will make it so we never have periods where it is hard to find a match for players on the bottom or top. The search in all playlists will expand from a tiny gap up to the maximum allowed gap (half the distribution) over 2.5 minutes.The risk we are taking here is that this will allow top players into matches with Plats in rare occasions. While this is true, the adaptive nature of the new rules will make sure this only happens if the only available population are those Plat players. The rules still try really hard for very tight matches at first, and will only allow those uneven ones as a last ditch effort to make a match in under 5 minutes.Playlists that have healthy populations will probably not notice any changes, especially if they search Focused.We are also seeing if we can increase that 5-minute wait time if this results in too many uneven matches.Also, we noticed we had a few rules in all our playlists that were causing the matchmaker to ignore tighter matches for edge-case reasons that we didn’t need anymore. We removed those extra rules, and this should result in even tighter than previous matches under some scenarios.