Models for measuring anthelmintic drug efficacy for parasitologists

•Modern statistical methods offer robust ways to estimate anthelmintic drug efficacy.•Marginal models permit robust inference on population covariates of drug efficacy.•Mixed models allow inference on individuals and quantify inter-individual variation.•Models may be used to detect changing drug efficacy during mass drug administration.

Anthelmintic drug efficacy (ADE) is generally estimated as a population average effect, despite drug responses varying among individuals according to a variety of measurable and non-measurable factors. Model-based and/or individual-level analyses are scarce and often methodologically frail. We propose that wider application of marginal and mixed models would offer benefits to the evaluation of ADE. We demonstrate, with a worked example, how model-based analyses: (i) capture the effects of correlation among hierarchically structured longitudinal data on estimates of ADE; (ii) permit robust inference on the association of measurable factors with ADE; and (iii) enable estimation of variation among individual-level estimates of ADE. The application of modelling approaches is discussed in the context of mass drug administration-based control of human helminthiases.