GammaFrailty: Gamma Frailty Regression Models with Multiple Baseline
Distributions
Implements univariate gamma frailty regression models for
survival data with six different baseline distributions: the Arvind
distribution (Pandey et al., 2024), the Lindley distribution
(Lindley, 1958), the Linear Failure Rate distribution (Bain, 1974),
the Power Xgamma distribution (Tyagi et al., 2022), the Modified
Topp-Leone distribution (Singh et al., 2025), and the Power Failure
Rate distribution (Mugdadi, 2005). The package supports uncensored
(complete) and censored data (right, left, interval, and progressive
censoring) with and without covariates. It provides maximum likelihood
estimation, standard errors, confidence intervals, t-statistics,
p-values, Akaike Information Criterion (AIC), Bayesian Information
Criterion (BIC), a bootstrap approximation of the Widely Applicable
Information Criterion (WAIC), k-fold cross-validation, variance
inflation factors, R-squared, adjusted R-squared, Mean Squared Error
(MSE), Mean Absolute Error (MAE), Root Mean Squared Error (RMSE), an
overall model F-test, frailty variance estimation, survival
probabilities at user-specified time points, median survival, expected
survival within a fixed window, risk predictions, marginal
predictions, martingale and deviance residuals, standardized and
studentized residuals, leverage values, Cook's distance, Difference
in Fits (DFFITS), Difference in Betas (DFBETAS), and a comprehensive
suite of diagnostic and survival plots including Kaplan-Meier overlays
and coefficient forest plots. Random number generation is available
for each baseline distribution and the full frailty model, and a
simulation study function evaluates parameter recovery across sample
sizes and censoring scenarios.
References are Lindley (1958) <doi:10.1111/j.2517-6161.1958.tb00278.x>,
Mugdadi (2005) <doi:10.1016/j.amc.2004.09.064>,
Bain (1974) <doi:10.1080/00401706.1974.10489237>,
Singh, Tyagi, Singh, and Tyagi (2025)
<https://ph02.tci-thaijo.org/index.php/thaistat/article/view/257215>,
Pandey, Singh, Tyagi, and Tyagi (2024)
<https://ssca.org.in/journal.html>, and
Tyagi, Kumar, Pandey, Saha, and Bagariya (2022)
<https://ijsreg.com/>.
| Version: |
0.1.0 |
| Depends: |
R (≥ 4.0.0) |
| Imports: |
survival, maxLik, numDeriv, MASS, stats, graphics, grDevices, utils |
| Suggests: |
testthat (≥ 3.0.0), knitr, rmarkdown |
| Published: |
2026-06-18 |
| DOI: |
10.32614/CRAN.package.GammaFrailty (may not be active yet) |
| Author: |
Shikhar Tyagi 
[aut, cre] |
| Maintainer: |
Shikhar Tyagi <shikhar1093tyagi at gmail.com> |
| License: |
GPL-3 |
| NeedsCompilation: |
no |
| Language: |
en-US |
| CRAN checks: |
GammaFrailty results |
Documentation:
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