Estimation and Additional Tools for Alternative Shared Frailty Models R package extrafrail version 1.14 Provide estimation and data generation tools for new multivariate frailty models. This version includes the gamma, inverse Gaussian, weighted Lindley, Birnbaum-Saunders, truncated normal, mixture of inverse Gaussian, mixture of Birnbaum-Saunders, generalized exponential and Jorgensen-Seshadri-Whitmore as the distribution for frailty terms. For the basal model, it is considered a parametric approach based on the exponential, Weibull and the piecewise exponential distributions as well as a semiparametric approach. For details, see Gallardo et al. (2024) <doi:10.1007/s11222-024-10458-w>, Gallardo et al. (2025) <doi:10.1002/bimj.70044>, Kiprotich et al. (2025) <doi:10.1177/09622802251338984> and Gallardo et al. (2025) <doi:10.1038/s41598-025-15903-y>. Software Depends: R (>= 4.0.0), stats Imports: survival, pracma, expint, msm Suggests: frailtyHL Diego Gallardo <dgallardo@ubiobio.cl> Comprehensive R Archive Network (CRAN) Diego Gallardo [aut, cre], Marcelo Bourguignon [aut], John Santib<c3><a1><c3><b1>ez [ctb], Gilbert Kiprotich [ctb], Pedro Ramos [ctb], Thomas Augustin [ctb], Zohreh Mohammadi [ctb] GPL (>= 2) 2025-08-24 application/tgz https://CRAN.R-project.org/package=extrafrail doi:10.32614/CRAN.package.extrafrail