Relative potency factors calculation

Relative potency factors (RPF s) describe the potency of substances with respect to a defined effect, relative to the potency of a chosen index or reference substance. RPFs are provided as data or computed from hazard characterisations. The RPF for substance $i$ is defined by the ratio of hazard characterisation value (POD) for the index substance ($\mathtt{ref}$) and the hazard characterisation value for substance $i$. That is,

$${\mathtt{RPF}}_i={\mathtt{POD}}_{\mathtt{ref}}/{\mathtt{POD}}_i.$$

When hazard characterisations are resampled in the uncertainty runs, RPFs are recomputed based on the bootstrapped hazard characterisations. In this way, RPF uncertainty is included in the uncertainty analysis.