Bookbreaker for +EV bettors
Your edge is a model output. How wrong might it be?
A +EV number is a model output, and the model is a devig you did not choose. On a -145 / +125 moneyline the four standard methods give the favourite 57.11% to 57.50% — 0.39 points apart on a market where 2% is a good edge.
What the screen shows instead of one number
EV +5.48% band +5.00%..+5.96% fill 94% → realised +5.13%
The band is what the four methods allow. An edge that only survives the friendliest one is a modelling artefact, and the screen filters those out by default rather than showing them and hoping you notice.
Which devig is right for your markets
Nobody knows in advance, and the answer differs between an NBA total and a tennis outright. So it is measured: every graded bet feeds a comparison of which method predicted the closing line, and the weights update — but only if the new ones beat the old ones on a slice of your record they were not fitted on.