Lisa White, Professor of Modelling and Epidemiology at our MORU unit in Thailand, tells us how we can use mathematical and economic modelling to better use limited resources to control or eradicate tropical diseases Mathematical modelling, particularly when combined with economical modelling, allows researchers and policy makers to determine the most effective interventions to fight infectious diseases such as malaria. We can use those models to explore ‘what ifs’ scenarios, at country or province level, save more lives and limit costs.