API Reference

The response

The Surv object, the spine of every analysis.

Kaplan-Meier survival and Nelson-Aalen cumulative hazard.

Cox proportional hazards and parametric AFT models.

CoxPH: Cox proportional hazards model.
CoxNet: Elastic-net penalized Cox proportional hazards model.
ZPHResult: Proportional-hazards test results (Grambsch-Therneau).
AFT: Parametric accelerated failure time model.
RoystonParmar: Royston-Parmar flexible parametric survival model (proportional hazards scale).

Cumulative incidence, the Fine-Gray model, and multi-state transition probabilities.

AalenJohansen: Aalen-Johansen estimator of cumulative incidence functions for competing risks.
FineGray: Fine-Gray subdistribution hazard model for a competing-risks endpoint.
MultiState: Aalen-Johansen estimator of multi-state transition and occupancy probabilities.

The log-rank test, trend tests for ordered groups, the G-rho (Fleming-Harrington) family, and restricted mean survival time (RMST) comparisons.

logrank_test(): Compare survival across groups using the weighted log-rank (G-rho) test.
trend_test(): Test for linear trend across ordered groups using the log-rank test family.
pairwise_logrank_test(): Pairwise log-rank tests for all group pairs with multiple-comparison correction.
TestResult: The outcome of a log-rank group comparison test.
rmst_test(): Test for equality of RMST across two or more groups.
rmst_diff(): Compute RMST difference between two groups with confidence interval.
pairwise_rmst_test(): Pairwise RMST tests for all group pairs with multiple-comparison correction.
RMSTResult: Results of an RMST comparison test or difference calculation.
logrank_n_events(): Number of events needed for the log-rank test to reach a target power.
logrank_power(): Power of the log-rank test given the number of observed events.
logrank_sample_size(): Total sample size needed for the log-rank test to reach a target power.

Concordance and the IPCW Brier score.

concordance_index(): Harrell’s concordance index: discrimination of risk scores against observed survival.
brier_score(): IPCW (Graf) Brier score of predicted survival probabilities at specified times.
integrated_brier_score(): Integrated (time-averaged) Brier score across multiple time points.
cross_validate(): Evaluate a survival model’s out-of-sample performance using k-fold cross-validation.

plotnine survival curves and aligned numbers-at-risk tables.

plot_survival(): Plot Kaplan-Meier survival curve(s) with Altair.
risk_table(): Return the numbers-at-risk table as a standalone Altair chart.

The risk-set / event-table tabulation shared by KM, log-rank, and Cox.

EventTable: Per-time risk-set tabulation (optionally within strata).
event_table(): Tabulate the event history: risk sets and events at each observed time.