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NelsonAalenCurve

A Nelson-Aalen cumulative-hazard curve.

public sealed record NelsonAalenCurve(SurvivalStep[] Steps, double[] CumulativeHazard)

Parameters — Steps are the curve's steps, ascending in time and starting at zero. CumulativeHazard holds the accumulated hazard, one entry per step.

Example — the hazard keeps rising where survival cannot fall further.

using Lodestar.Survival;

NelsonAalenCurve curve = NelsonAalen.Estimate([1, 2, 3], [true, true, true]);

double atStart = curve.CumulativeHazard[0];  // => 0
double atEnd = curve.CumulativeHazard[3];  // => 1.833…

Remarks — Steps is the same table KaplanMeierCurve carries, because both estimators are built on one risk table. Comparing the two on the same sample is therefore an index-by-index comparison with no alignment step.

The last value above is 1/3 + 1/2 + 1/1. Kaplan-Meier on that sample ends at zero; this ends at 1.833, and the difference is the information a curve pinned to zero has lost.

Applies to — net10.0, netstandard2.0.

See also — NelsonAalen.Estimate, SurvivalStep.