## RMSTResult


Results of an RMST comparison test or difference calculation.


Usage

``` python
RMSTResult(
    estimate,
    se,
    lower_ci,
    upper_ci,
    statistic,
    p_value,
    method,
    group1,
    group2,
    rmst1,
    se1,
    rmst2,
    se2,
    tau,
    estimand="difference",
    stratified=False,
    conf_level=0.95
)
```


This class stores the results of RMST group comparisons in a structured format, including point estimates, confidence intervals, and hypothesis test statistics.


## Attributes


`estimate: float`  
The point estimate of RMST difference, ratio, or percentage difference between groups.

`lower_ci: float`  
Lower bound of the confidence interval for the estimate.

`upper_ci: float`  
Upper bound of the confidence interval for the estimate.

`se: float`  
Standard error of the estimate.

`statistic: float`  
Test statistic (z-score for Wald test) for the null hypothesis of no difference.

`p_value: float`  
Two-tailed p-value for the hypothesis test. Small values (typically \< 0.05) indicate significant differences between groups.

`method: str`  
Human-readable description of the comparison method, e.g., `"RMST difference (tau=365)"`.

`group1: Any`  
Label of the first group (minuend in difference).

`group2: Any`  
Label of the second group (subtrahend in difference).

`rmst1: float`  
RMST estimate for group 1 at tau.

`se1: float`  
Standard error of RMST for group 1.

`rmst2: float`  
RMST estimate for group 2 at tau.

`se2: float`  
Standard error of RMST for group 2.

`tau: float`  
The restriction time tau used in the RMST calculation.

`estimand: str`  
The type of estimand: `"difference"`, `"ratio"`, or `"percentage_difference"`.

`stratified: bool`  
Whether this is a stratified comparison (True) or pooled (False).

`conf_level: float`  
Confidence level used for interval estimation (the default is `0.95`).


## Examples

Compare RMST between two groups:


``` python
import greenwood as gw

lung = gw.load_dataset("lung", backend="polars")
y = gw.Surv.right(lung["time"], event=(lung["status"] == 2))

result = gw.rmst_test(y, tau=365, group=lung["sex"])
result
```


    RMSTResult(method='RMST difference (tau=365)', estimate=-55.9703, se=14.9581, 95% CI=[-85.2877, -26.6529], p_value=0.0001827)


Access individual components:


``` python
result.estimate  # difference between groups
result.p_value   # significance
result.se        # standard error
```


    np.float64(14.958125860424103)