afttest-package: afttest: Diagnostics for Semiparametric Accelerated Failure...

In afttest: Model Diagnostics for Accelerated Failure Time Models

afttest: Diagnostics for Semiparametric Accelerated Failure Time Models

Description

The afttest package provides diagnostic tools for semiparametric accelerated failure time (AFT) models. It supports formal model checking and graphical assessment for fitted AFT models, providing a unified framework for evaluating model adequacy and interpreting results.

Details

The main interface is the generic function afttest, which accepts either a formula or fitted model objects from the aftgee package, including aftsrr and aftgee.

Implemented diagnostic procedures include:

• Omnibus test (testType = "omnibus"), for assessing overall model adequacy;

• Link function test (testType = "link"), for evaluating the specified link function;

• Functional form test (testType = "covForm"), for checking whether a continuous covariate is correctly specified.

The package supports diagnostic inference for:

• rank-based estimators with non-smooth (eqType = "ns") and induced-smoothed (eqType = "is") estimating equations;

• least-squares estimators (estMethod = "ls") fit through generalized estimating equations.

For computational efficiency, afttest implements a fast multiplier bootstrap procedure. When linApprox = TRUE, an asymptotic linear approximation is used to avoid repeated iterative model fitting, substantially reducing computation time relative to standard resampling with linApprox = FALSE.

Author(s)

Maintainer: Woojung Bae [e-mail] (ORCID)

Authors:

• Dongrak Choi (ORCID)

• Jun Yan (ORCID)

• Sangwook Kang (ORCID)

References

Bae, W., Choi, D., Yan, J., & Kang, S. (2025). afttest: Model diagnostics for semiparametric accelerated failure time models in R. arXiv preprint arXiv:2511.09823.

Choi, D., Bae, W., Yan, J., & Kang, S. (2024). A general model-checking procedure for semiparametric accelerated failure time models. Statistics and Computing, 34(3), 117.

See Also

Useful links:

• https://github.com/WooJungBae/afttest

• Report bugs at https://github.com/WooJungBae/afttest/issues

afttest documentation built on March 22, 2026, 5:06 p.m.