fssg comes with a number of native distributions. These
distributions are custom built, or sourced from other great R packages.
The below table gives additional information on all included
distributions.
Please note, AFT/PH specifications are based on model results reviewing by the fssg author team, and may not perfectly reflect how the distribution works in reality. In general, for distributions marked as AFT, a higher effect size (i.e. a positive one) usually implies longer survival time. For distributions marked as PH, a higher effect size usually implies a higher hazard rate. Please take the time to verify that your interpretation of these coefficients is consistent with the model’s prediction before publishing or reporting.
| fssg_names | distribution | package_source | varying_parameter | model_specification |
|---|---|---|---|---|
| genf | Generalized F | flexsurv | mu | AFT |
| genf.orig | Generalized F (alternative) | flexsurv | mu | AFT |
| gengamma | Generalized Gamma | flexsurv | mu | AFT |
| gengamma.orig | Generalized Gamma (alternayive) | flexsurv | scale | AFT |
| exp | Exponential | flexsurv | rate | PH |
| weibull | Weibull | flexsurv | scale | AFT |
| weibullPH | Weibull (PH form) | flexsurv | scale | PH |
| lnorm | Log Normal | flexsurv | meanlog | AFT |
| gamma | Gamma | flexsurv | rate | AFT |
| gompertz | Gompertz | flexsurv | rate | PH |
| llogis | Log-Logistic | flexsurv | scale | AFT |
| exponential | Exponential | flexsurv | rate | PH |
| lognormal | Lognormal | flexsurv | meanlog | AFT |
| betaprime | Beta-Prime | extraDistr | scale | AFT |
| cauchy_scale | Cauchy | stats | scale | AFT |
| cauchy_location | Cauchy | stats | location | AFT |
| dagum | Dagum | VGAM | scale | AFT |
| exp_log | Exponential Logarithm | VGAM | scale | AFT |
| gen_extr_val | Generalized Extreme Value | extraDistr | sigma (scale) | AFT |
| gen_extr_val_location | Generalized Extreme Value | extraDistr | mu (location) | AFT |
| fatigue2_scale | Fatigue / Birnbaum Saunders (No location parameter) | extraDistr | beta(scale) | AFT |
| fatigue3_scale | Fatigue / Birnbaum Saunders | extraDistr | beta(scale) | AFT |
| fatigue3_location | Fatigue / Birnbaum Saunders | extraDistr | mu (location) | AFT |
| fold_norm_scale | Fold-Normal | VGAM | sd | AFT |
| fold_norm_location | Fold-Normal | VGAM | mean | Unclear |
| feller_pareto | Feller-Pareto | actuar | rate | PH |
| frechet | Frechet | extraDistr | sigma (scale) | AFT |
| gamma_gompertz | Gamma-Gompertz | fssg | b (scale) | PH |
| gumbel | Gumbel | extraDistr | sigma (scale) | AFT |
| gumbel_T2 | Gumbel Type II | VGAM | scale | AFT |
| hypertab_a | Hypertabatastic | fssg | a | PH |
| hypertab_b | Hypertabatastic | fssg | b | PH |
| inv_chisq | Inverse Chi-squared | extraDistr | nu | PH |
| inv_gamma | Inverse Gamma | extraDistr | beta (scale) | AFT |
| inv_gaussian_scale | Inverse Gaussian | VGAM | mu (location) | AFT |
| inv_gaussian_location | Inverse Gaussian | VGAM | lambda (scale) | AFT |
| inv_lind | Inverse Lindley | fssg | theta | AFT |
| laplace | Laplace | extraDistr | sigma (scale) | AFT |
| levy | Levy | VGAM | scale | AFT |
| lindley | Lindley | VGAM | theta | PH |
| log_cauchy_location | Log Cauchy | fssg | mu (location) | AFT |
| lomax_scale | Lomax | extraDistr | lambda (scale) | PH |
| lomax_shape | Lomax | extraDistr | kappa (shape) | PH |
| nakagami | Nakagami | VGAM | scale | AFT |
| pareto_1 | Pareto I | VGAM | scale | AFT |
| pareto_2 | Pareto II | VGAM | scale | AFT |
| pareto_3 | Pareto III | VGAM | scale | AFT |
| pareto_4 | Pareto IV | VGAM | scale | AFT |
| rayleigh | Rayleigh | extraDistr | sigma | AFT |
| rice_scale | Rice | VGAM | vee | AFT |
| rice_location | Rice | VGAM | sigma | AFT |
| shift_gomp | Shifted Gompertz | extraDistr | b | PH |
| sinmad | Singh Madalla / Burr Type 12 | VGAM | scale | AFT |
| scale_inv_chisq | Scaled Inverse Chi-squared | extraDistr | tau | AFT |