Changelog
Source:NEWS.md
    Version 0.9 (2025/05/02)
- 
smooth_model = "random_walk"made the default insurvextrap(), following Timmins et al..
Version 0.8.16 (2025/02/26)
- 
rmst()and related functions are now faster, with the new Gauss-Legendre integration method. Thanks to Iain Timmins.
Version 0.8.15 (2024/07/01)
- Random walk prior for the coefficients changed to a first-order weighted model, following Phillippo et al., so that the expected smoothness accounts for the knot spacing.
Version 0.8.13 (2024/03/05)
- Bug fix for models with external data and either nonproportional hazards or covariates on cure probability.
Version 0.8.12 (2024/01/06)
- 
irmst,hazard_ratioandhrtimetidied. Fix of bug inirmstintroduced in v0.8.9, and all now have asampleargument.
Version 0.8.11 (2023/12/28)
- Outputs standardised over the covariate values of a reference population can now be produced using the new standardise_to()function.
Version 0.8.10 (2023/12/24)
- loono longer ignores covariates on the cure probability in cure models.
- More internal refactoring of code to produce outputs. 
Version 0.8.9 (2023/12/22)
- Cleaned and simplified internal code for model outputs ( - rmst,- survivaletc.).
- rmstnow outputs a tibble, and credible limits in the default output are renamed to- lowerand- upperfor consistency with- survivaland- hazard.
- Arrays now allowed for - coefargument in- dsurvsplineand related functions.
Version 0.8.8 (2023/12/19)
- Background hazards in additive hazards models can now be stratified, using the new - backhaz_strataargument to- survextrap(). This argument names stratifying variables (e.g. age group) that should be in both the background hazards and the individual and/or external data.
- Bug fix for - hsurvmspline_waneand- dsurvmspline_wanewhere offsets were not implemented correctly. This affected hazard predictions for models that included both background hazards and treatment effect waning.
Version 0.8.7 (2023/10/29)
- A random walk prior can now be specified for the spline coefficients, by smooth_model = "random_walk".
Version 0.8.6 (2023/10/24)
- Non-proportional hazards models can now be applied to a subset of the covariates, by supplying a formula as the - nonpropargument to- survextrap.
- Prior simulation functions such as - prior_samplenow require an explicit covariate model, specified through- formulaand- newdata, rather than a design matrix- X. These functions now fully support nonproportional hazards models and cure probabilities with associated regression models.
Version 0.8.5 (2023/09/30)
- Code for constructing msplinespecification objects tidied, with newmspline_initandmspline_list_initfunctions.
Version 0.8.4 (2023/09/09)
- Deprecated Stan array syntax updated. The package now requires rstanversion 2.26.
Version 0.8.2 (2023/06/14)
- Individual data can now be excluded, so that the model is fitted to external data alone.
Version 0.8 (2023/05/06)
The GitHub commit on 6 May 2023 implemented several changes that are listed here. survextrap is now in “beta” status. All major features are now implemented, but there may still be some lack of polish.
New features
- A new vignette - cetuximab, giving an in-depth case study of a realistic use of- survextrap. To be included in a forthcoming paper.
- 
Improvements to usability and stability of M-splines: - iknotsand- bknotsare replaced by a single- knots, and the lower boundary knot is always fixed at zero.
- add_knotscan be used to add user-defined knots to the default ones. See the case study.
- New function - mspline_specto define M-spline knots based on data, in advance of fitting any models.
- M-splines can now be smoother at the final knot, through an option - bsmooth, which is on by default. Thanks to Iain Timmins for the suggestion.
 
- Incremental restricted mean survival time ( - irmst) added.
- Any summary of the posterior distribution can be produced by supplying a list of summary functions (e.g. - mean,- quantiles) to output functions (such as- rmstand- survival).
- Leave-one-out cross validation for external data. 
Bug fixes and improvements
- Bug fix for - hsurvmspline()(hence- hazard()) which was using the wrong tail end of- psurvmspline().
- Waning models no longer ignore non-proportional hazards and cure. Waning vignette merged into the methods vignette. 
- Leave-one-out cross validation now supports models with background hazards. 
- More consistent naming of arguments and variables (e.g. - hscalefor hazard scale, and- hsdfor hazard smoothing parameter).
- More information given when printing fitted model objects. 
- Thorough documentation polishing and code tidying.