From: Vitality models found useful in modeling tag-failure times in acoustic-tag survival studies
Failure–time functions | Hazard function description |
---|---|
Exponential | Constant over time |
Weibull (2) | Linear or log-linear monotonic increase/decrease |
Weibull (3) | Linear or log-linear monotonic increase/decrease with a shift that represents a guaranteed (“failure free”) period |
Log-normal | Monotonic decrease or dome-shaped |
Log-logistic | Monotonic decrease or dome-shaped. Allows for steeper decrease from apex than the log-normal |
Gompertz | Constant initial hazard, which can remain constant or then have a quadratic increase/decrease |
Gamma | Monotonic increase or decrease to a hazard rate of 1 |
Generalized gamma | Monotonic increase or decrease to a specific hazard rate of \(\alpha\) |
Vitality 2009 | Initial hazard rate followed by a shift in rate |
Vitality 2013 | Initial hazard rate followed by a shift in rate |