An open, Jev-style decision model: typed questions in, calibrated probabilities out, all read off one distribution over tomorrow's high. Every chart here is scored out of sample against the market's own price at the same timestamp. Code and raw results: physicalreasoning/isotherm.
Log score gain in nats per ladder. The simple pools went to zero in 2025; isotherm stays positive but decays.
Every model against the market with a 95% date-block CI. The control is trained on labels sampled from the market, so it can only win if the pipeline leaks.
Every bucket as a yes/no question: predicted probability against how often it happened.
Last 12 months. Adding NBM, the forecast behind weather.gov, no longer helps. GFS MOS still does.
isotherm minus market. Blue is better than the market, red worse; a dot marks a CI that excludes zero.
$10k bankroll, Kalshi fees. Each quarter trades the config with the best Sharpe on earlier quarters only.
Deflated Sharpe corrects for the 28 configs tried; PBO is the chance the in-sample winner lands below the median out of sample.
Believable needs DSR ≥ 0.95 and PBO ≤ 0.20. Only the daily lows 4pm cell got there, and its sealed test made $36.
Alpha against the mid versus what execution costs. Takers pay the spread; makers earn it and lose it again to adverse selection.
The configuration nested selection used most, under worse fills, higher fees, different size and participation.
Strategy and pass rule pushed before scoring; July to October 2026 scored once.
The best backtest in the project. The placebos flipped from profit to loss in the sealed weeks: the young market had corrected.
Highs profits roughly halved each month. Lows were flat.
17 Kalshi series. Weather has history, room in the spread and a free forecast. Point size: log median volume per event.
92k synthetic ladders from 55 stations Kalshi does not list. Helps when real data is scarce, slightly hurts with all of it.
Elo and starting pitchers pooled with the market, by time before first pitch.
Pooling the market with each forecast, February to August 2026.
The frozen strategy scores every city daily at 16:00 local and commits its paper trades before the outcome exists. Ledger on the shadow-ledger branch.
Rolling 30-day log score gain against the market. STOP when two consecutive windows sit fully below zero.