Home › Survival › Survival estimators

The time by which each subject's survival falls to a level: lifelines' predict_percentile.

public double[] PredictPercentile(ReadOnlySpan<double> design, double probability)

Parameters — design holds the subjects' covariates row-major, FeatureCount per row; empty for the one subject of a fit with no covariate. probability is the survival level, strictly inside (0, 1); a half for the median.

Returns — one time per subject.

Exceptions — ArgumentException when design is not whole rows of finite covariates. ArgumentOutOfRangeException when probability is not strictly inside (0, 1). ArgumentException naming design also when it is more cells than one array holds (#1614).

Example — the time by which three quarters have had the event.

using Lodestar.Survival;

double[] dose = [1.0, 2.0, 0.5, 3.0, 0.0, 1.5, 0.0, 2.5, 1.0, 0.5];
double[] months = [5, 8, 12, 3, 15, 9, 20, 6, 11, 14];
bool[] died = [true, true, false, true, true, true, false, true, true, false];

AftSummary fit = AcceleratedFailureTime.Fit(AftModel.Weibull, dose, months, died, featureCount: 1);

double[] times = fit.PredictPercentile([0.0, 2.0], 0.25);
double untreated = Math.Round(times[0], 6);   // => 22.614671
double twoUnits = Math.Round(times[1], 6);    // => 7.540571

Remarks — the level is a survival probability, as lifelines' is: 0.25 is the time a quarter are still event-free, later than the median. Each model inverts its survival function in closed form.

Applies to — net10.0, netstandard2.0.

See also — AftSummary, AftSummary.PredictMedian, ParametricFit.Percentile.