Fig. 2. Illustration of how population models can enhance dose-response assessment.

Panel a: Populations contain a mix of individual dose-response curves, which when aggregated, can be constitute the population-level dose-response relationship, adapted from the National Academies report Science and Decisions (NAS 2009). Panel b: Comparison of individual-level concentration-response data and the modeled population-level dose-response curve for DO mice exposed to benzene, based on data reported in French et al. (2015). The dose at which a 10% increase in bone marrow micronuclei occurs at the population level is lower than the dose at which this occurs in B6C3F1 mice, suggesting using a single strain can be misleading. Panel c: Comparison of individual-level concentration-response data and the modeled population-level dose-response curve for cytotoxicity responses across 1086 lymphoblastoid cell lines exposed to zinc pyrithione, based on data reported in Abdo et al. (2015). The population concentration-response is based on fraction of cell lines at each concentration for which a 10% increase in cytotoxic response occurs (i.e., where the individual curves cross the dashed horizontal line in the left panel), or equivalently, the cumulative distribution of EC₁₀ values.