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Quant Library · Match pricing · Football

Laplace Uncertainty

A band around every probability, from the curvature of the likelihood at its optimum.

The fitted parameters have a covariance: the inverse Hessian of the negative log likelihood. Draw from it, re-price, and you have a distribution over prices rather than a single number.

Inputs

What it takes

3
NameTypeUnitsWhere it comes from
fitfitted model-the Match Price Engine
matchesthe weighted match list the fit used-the same source
draws optionalintcountyour choice; 400 is enough for a 90% interval
Outputs

What it gives back

3
NameTypeUnitsNotes
covariancek x k array-
interval(low, high) per outcomeprobability
widthfloatprobability pointswhat the Predict page calls How sure
Method

How it works

  1. Compute the Hessian of the weighted negative log likelihood at the optimum by central differences.
  2. 2 further steps in the licensed specification
Assumptions
  • The likelihood is approximately quadratic near its optimum, which is the usual large-sample argument and is weakest for teams with few matches.
Limits
  • It is parameter uncertainty only. It says nothing about the model being the wrong shape, which is the larger error.
  • 1 further limits in the licensed specification
Validation

What it was measured at

ok

The band is reported on every price the Arena serves; these are its properties rather than a score.

Interval90%on the favourite's probability, from the parameter covariance
Draws400from the multivariate normal at the optimum
Typical width, established side3 to 5 pointsseveral seasons of matches behind the fit
Typical width, promoted side in August10 to 15 pointswhich is the point of printing it
What it does not covermodel errorfor coverage that survives the model being wrong, licence the conformal sets
In the package
  • The full specification: inputs, method, assumptions and limits
  • The validation panel as measured on the day of purchase
  • A reference implementation extracted from the running source
  • Perpetual commercial use for one entity

Reference modules:

  • 1 module(s), named in the licensed specification and shipped in the package
Read this before you buy. The platform's own walk-forward tests say the closing line forecasts football better than these models do. What they give you is a coherent price for every market and match, before the market opens, with the band and the working attached. Any model here that has been beaten by something simpler says so in its limits, and the validation panel above is generated from the platform's result files rather than typed in.