Stressors, such as toxicants, can cause mortality among organisms. Interestingly, not all individuals will die at the same time in the same exposure treatment, and the number of deaths will change with exposure time.
The pattern of mortality will also depend on the exposure profile (e.g. constant versus pulsed exposure, fluctuating or time-variable exposure). Making sense of these issues requires mechanism-based models, known as toxicokinetic-toxicodynamic (TKTD) models. For mortality, almost all published TKTD models can now be viewed as members of an over-arching framework: the General Unified Threshold model of Survival (GUTS).
The GUTS software is a user-friendly, robust, freely-available and open-source software for standard GUTS applications.
The GUTS software should be released in December 2019.