# greenwood

> Modern survival analysis for Python: Narwhals-native, R-validated, beautifully visualized.

## Docs

### API Reference

#### The response
> The Surv object, the spine of every analysis.

- [Surv](https://rich-iannone.github.io/greenwood/reference/Surv.html): A validated time-to-event response for survival analysis
- [CensoringType](https://rich-iannone.github.io/greenwood/reference/CensoringType.html): The censoring flavor of a `Surv` response

#### Non-parametric estimators
> Kaplan-Meier survival and Nelson-Aalen cumulative hazard.

- [KaplanMeier](https://rich-iannone.github.io/greenwood/reference/KaplanMeier.html): Kaplan-Meier product-limit estimator of the survival function
- [NelsonAalen](https://rich-iannone.github.io/greenwood/reference/NelsonAalen.html): Nelson-Aalen estimator of the cumulative hazard

#### Regression
> Cox proportional hazards and parametric AFT models.

- [CoxPH](https://rich-iannone.github.io/greenwood/reference/CoxPH.html): Cox proportional hazards model
- [CoxNet](https://rich-iannone.github.io/greenwood/reference/CoxNet.html): Elastic-net penalized Cox proportional hazards model
- [ZPHResult](https://rich-iannone.github.io/greenwood/reference/ZPHResult.html): Proportional-hazards test results (Grambsch-Therneau)
- [AFT](https://rich-iannone.github.io/greenwood/reference/AFT.html): Parametric accelerated failure time model
- [RoystonParmar](https://rich-iannone.github.io/greenwood/reference/RoystonParmar.html): Royston-Parmar flexible parametric survival model (proportional hazards scale)

#### Competing risks & multi-state
> Cumulative incidence, the Fine-Gray model, and multi-state transition probabilities.

- [AalenJohansen](https://rich-iannone.github.io/greenwood/reference/AalenJohansen.html): Aalen-Johansen estimator of cumulative incidence functions for competing risks
- [FineGray](https://rich-iannone.github.io/greenwood/reference/FineGray.html): Fine-Gray subdistribution hazard model for a competing-risks endpoint
- [MultiState](https://rich-iannone.github.io/greenwood/reference/MultiState.html): Aalen-Johansen estimator of multi-state transition and occupancy probabilities

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

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

#### Prediction performance
> Concordance and the IPCW Brier score.

- [concordance_index](https://rich-iannone.github.io/greenwood/reference/concordance_index.html): Harrell's concordance index: discrimination of risk scores against observed survival
- [brier_score](https://rich-iannone.github.io/greenwood/reference/brier_score.html): IPCW (Graf) Brier score of predicted survival probabilities at specified times
- [integrated_brier_score](https://rich-iannone.github.io/greenwood/reference/integrated_brier_score.html): Integrated (time-averaged) Brier score across multiple time points
- [cross_validate](https://rich-iannone.github.io/greenwood/reference/cross_validate.html): Evaluate a survival model's out-of-sample performance using k-fold cross-validation

#### Visualization
> plotnine survival curves and aligned numbers-at-risk tables.

- [plot_survival](https://rich-iannone.github.io/greenwood/reference/plot_survival.html): Plot Kaplan-Meier survival curve(s) with Altair
- [risk_table](https://rich-iannone.github.io/greenwood/reference/risk_table.html): Return the numbers-at-risk table as a standalone Altair chart

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

- [EventTable](https://rich-iannone.github.io/greenwood/reference/EventTable.html): Per-time risk-set tabulation (optionally within strata)
- [event_table](https://rich-iannone.github.io/greenwood/reference/event_table.html): Tabulate the event history: risk sets and events at each observed time