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SurvivalStep

One step of a survival or cumulative-hazard curve.

public sealed record SurvivalStep(double Time, int AtRisk, int Events, int Censored)

Parameters — Time is the duration the step sits at. AtRisk is how many subjects were still at risk immediately before it. Events is how many had the event at it, Censored how many left without it.

Example — reading the risk set down a curve.

using Lodestar.Survival;

KaplanMeierCurve curve = KaplanMeier.Estimate([1, 2, 3], [true, false, true]);

double opensAt = curve.Steps[0].Time;  // => 0
int everyone = curve.Steps[0].AtRisk;  // => 3
int afterCensoring = curve.Steps[2].AtRisk;  // => 2

Remarks — a step exists for every distinct duration, censorings included, so a time that removes subjects without moving the estimate is still visible. AtRisk is measured before the step rather than after, which is what makes Events / AtRisk the increment the estimators use.

The first step is always time zero with everyone at risk and nothing having happened — the shape lifelines' own event table has, and what lets a curve be plotted without inventing a first point.

Applies to — net10.0, netstandard2.0.

See also — KaplanMeierCurve, NelsonAalenCurve.