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The cliff survival profile answers a strategist’s question: if you put this compound on now, how likely is it to still be alive in ten laps? Each curve is the probability that a stint reaches a given lap without a cliff onset event, estimated with the Kaplan-Meier estimator from every comparable stint in the data. The scatter of where real stints actually ended is the live validation if the curve crosses 0.5 near the fitted model’s onset line, the cliff model is well calibrated.

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What it shows

The chart overlays a survival curve, a model reference line, and a validation scatter:
  • Survival curve S(t): the Kaplan-Meier probability a stint of this compound is still pre-cliff at lap t. At each lap where at least one cliff is observed, S(t) = S(t-1) × (1 − events / at-risk).
  • Censoring: a stint where the driver pitted before the cliff is censored it reduces the at-risk pool without contributing an event, because it only tells us the cliff had not happened yet, not that it never would.
  • Model onset line: the median cliff lap from the fitted survival model stored in dim_compounds_season.
  • Degradation overlay (right axis): cumulative expected degradation in seconds at the point each stint ended. Red dots mark a cliff observed before the pit; grey squares mark a pit before the cliff.
Rain laps and anomaly-flagged laps are excluded from both the survival curve and the scatter. The provenance footer shows the original fit date and the number of cross-season stints used.

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How to use it

  1. Select a compound and circuit from the filter bar; the curve and onset line reload for that combination.
  2. Read the 0.5 crossing the lap where survival drops to 50% is the median expected cliff lap.
  3. Compare the curve against the model line to judge calibration: a curve crossing 0.5 far from the model line signals a compound the model is mis-pricing here.
  4. Inspect the scatter a cluster of red dots earlier than the curve suggests drivers were pushed past the cliff; grey squares clustered early mean conservative, undercut-driven stops.

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Reading the signal correctly

Survival is conditional on reaching each lap, so the right-hand tail thins out as stints are pitted or end wide steps late in the curve come from a small at-risk pool, not a real cliff in probability.
Censored (pit-before-cliff) stints dominate short-stint circuits. Where almost every driver pits early for strategy rather than degradation, the curve is built mostly from censoring and should be read as a lower bound on tyre life, not the tyre’s true limit.

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Data source

The chart queries fct_cliff_prediction_features (the per-lap stint history) and dim_compounds_season (the fitted onset coefficients) via DuckDB-Wasm in the browser. The data window covers 2018–2024. For the full model definitions, see the fct_cliff_prediction_features reference and the dim_compounds_season reference.