August 2026
CPR ranking update
The simple version
We fixed how sure chalksta is about each player’s ranking (CPR).
The old weekly job kept that “how sure” knob almost stuck, so some people jumped too far in one week. The new math lets that knob move the way it was always supposed to.
Your CPR is still the same kind of number: 1050 is still 1050.
For the league we fully recrunched, current CPR was reset from a season replay through early May, then we started clean. Games after that were not folded back in on purpose — we are not mixing two different calculators.
If you play in chalksta — league night or Survivors — you can get a CPR. Some divisions may also turn on Stabilized handicaps: ranking can still move every week, but the scoresheet handicap waits until a rise or drop holds. That is optional and per division. Dynamic CPR mapping is unchanged unless your operator turns Stabilized on.
For the curious
CPR is a Glicko-2 rating used as-is (750 is 750). One rating period is one week. All of a player’s games that week go into a single update — not one update per match.
Each player has three stored values: μ (rating / CPR), φ (rating deviation, RD — how unsure we are), and σ (volatility). The expected score vs an opponent is:
E = 1 / (1 + 10−g(φopp)(μ − μopp)/400)
g(φ) = 1 / √(1 + 3φ²/π²)
When RD was stuck near 1.5 (and capped at 2.0), g(φ) was basically 1, so a couple of results could yank CPR around. Corrected RD typically sits around 12–22, so one week moves you less when we are already sure, and more when we are not.
New players start at 750 / RD 20 / volatility 0.010. τ (the constraint on volatility) is 0.5. An ERO uses a dummy opponent at 975 only when the score is 10 and the ERO flag is on. We now save μ, RD, and σ every week. If Monday’s job is missed, it catches up later.
League 1001: the replay ending 2026-05-04 is the new current CPR for mapped players. Play after that week was not replayed. Other leagues keep their CPR numbers; the first corrected weekly pass only rebases stuck old-scale RD (under 8) to 20 / 0.010, and leaves Jon-scale RD alone.
- Better Weekly CPR ranking — see CPR ranking update above. Same 1050 scale; the “how sure” math is fixed. Survivors games can count, and a first-time player can get a CPR after they play.
- New Weekend and special events — if your league uses Event Manager, you can register from a public link and follow the bracket or round-robin schedule. Opening a match takes you to the right scoresheet (captain, player, or spectator) based on who you are.
- New Print sheet — on a scoresheet you can print a blank portrait copy of the designed sheet to fill in at the table.
- Better Shared tournament links open a locked view of that one event, so you stay on the match you were sent. Survivors match boards are easier to read.
- Better Player Standings — names take less width, and points / survivors columns use shorter headers so more of the table fits on a phone.