hazardous.metrics.integrated_brier_score_survival#

hazardous.metrics.integrated_brier_score_survival(y_train, y_test, y_pred, times)#

Compute the Brier score integrated over the observed time range.

\[\mathrm{IBS} = \frac{1}{t_{max} - t_{min}} \int^{t_{max}}_{t_{min}} \mathrm{BS}(u) du\]

Note that this assumes independence between censoring and the covariates. When this assumption is violated, the IPCW weights are biased and the Brier score is not a proper scoring rule anymore. See [Gerds2006] for a study of this bias.

Parameters:
y_trainrecord-array, dictionnary or dataframe of shape (n_samples, 2)

The target, consisting in the ‘event’ and ‘duration’ columns. If the ‘event’ column holds more than 1 event types, they are automatically collapsed to a single event type to compute the Brier score of the “any-event” survival function estimate. This is only used to estimate the IPCW values to adjust for censoring in the evaluation data.

y_testrecord-array, dictionnary or dataframe of shape (n_samples, 2)

The ground truth, consisting in the ‘event’ and ‘duration’ columns. The same remark applies as for y_train with respect to the ‘event’ column.

y_predarray-like of shape (n_samples, n_times)

Survival probability estimates predicted at times.

timesarray-like of shape (n_times)

Times at which the survival probabilities y_pred has been estimated and for which we compute the Brier score.

Returns:
ibsfloat

See also

brier_score_survival

Time-dependent Brier score of a survival function estimate.

References

[Graf1999]

E. Graf, C. Schmoor, W. Sauerbrei, M. Schumacher, “Assessment and comparison of prognostic classification schemes for survival data”, 1999

[Gerds2006]

T. Gerds and M. Schumacher, “Consistent Estimation of the Expected Brier Score in General Survival Models with Right-Censored Event Times”, 2006