How it is built
A live win probability model looks at many historical games that passed through a similar state and asks how often the team in this position won — then adjusts for team strength. The pregame probability is the starting point; each new state updates it.
Leverage: why late plays move it more
Early in a game there is a lot of game left to average out any single event. Late, one play can decide most of what remains. The same touchdown or home run moves win probability a few points in the first quarter and tens of points in the last minutes. This sensitivity is called leverage.
Reading it well
- It is a probability, not a verdict. Teams at 85% lose about 15% of the time — and those comebacks are exactly the games people remember.
- Check whose model it is. Some live bars on the network come from a data provider, not a PropBetEdge model. The NBA models page states this explicitly for NBACast. Know which you are reading.
- It is calibrated (or not) like any model. Everything in Calibration applies.
Live models often cannot see injuries during the game, weather shifts or tactical changes until they show up in the score. A sudden, unexplained move in a market price can reflect information a state-based model does not have.