Caliber estimates your team’s win probability at the draft, written w(x): the chance you win from this state. Each lock then has a win probability added, ΔW = w(after) − w(before). That is the strip along the bottom.
w(x) is a logistic model of this draft. Gold, kills, dragons, and position are not in it: this desk stops when the game starts, and those features are not part of the pre-game read. What moves the number is map side, champion win rates, lane matchups, synergy, and, once names exist, each player’s record on the locked champion. Rank is a small extra. Recent form is smaller still.
- Map side is a small prior. Blue sits just above 50%.
- Champion strength is the role win rate, pulled toward average until the sample is large. A 40-game spike does not count as a 60% champion.
- Lane matchups keep only what the pairing adds beyond those two win rates. Ahri into Malzahar can move the draft even when both look ordinary alone. A thin sample falls back to the win rates.
- Synergy is the normalised win rate of two champions together, again shrunk by games. The bot-lane pair weighs more than a side pairing.
- Lane terms are added and then soft-capped, so five good lanes make a real favorite without printing 85%. One hard counter stays visible.
- Summoner spells place a champion in a lane. Smite is jungle, Heal is bot, Teleport is a solo lane. They do not add a win rate of their own.
- Your picks into theirs. Until you lock, the strip under the board scores champions for your role as if you locked them into this enemy draft. Owned champions are used when the client shares them.
- Your record during select. The client can score your mastery and your games on the champion you are hovering before the loading screen. Everyone else waits until names exist.
- Loading screen. Once names exist, each player’s win rate on the locked champion is scored against that champion’s usual win rate. The download asks Caliber’s server for those records. The Riot key stays on the server. Mastery is used only when that player has almost no games on the champion. Rank is included, small, because matchmaking already did most of that work. Recent form is lighter still.
- After the game. The draft’s probability and the result are saved on this PC, in
data/outcomes.jsonl. That log is how the weights can be checked later. It does not change the number.
Rates default to Emerald+ solo queue. A matchup percentage is a game win rate in games where that pairing happened, not a “won the lane” rate. Bans are shown and not scored: a ban’s value is the draft that didn’t happen, and this model doesn’t invent that counterfactual.
