How to better communicate exponential growth of infectious diseases
AbstractSustained non-pharmaceutical interventions (NPIs) can contain the spread of infectious disease when vaccines or treatments are not available1-3. The benefit of such behavioural adaptations can be modelled as the deceleration of the exponential growth of cases. Humans underestimate exponential growth, as has been documented in biological4, environmental5-6 and financial contexts7-13. Hence, they might also underestimate the benefit of reducing the exponential growth rate. Different ways of communicating the same scenario, i.e. frames, have been found to have a large impact on people’s evaluations and choices in the contexts of social behaviour14,15, risk taking16-19 and health care20-23. Here we show that framing matters for people’s assessment of the benefits of measures to mitigate the spread of infectious disease. In two commonly used frames, most subjects in our experiment drastically underestimate the number of cases mitigation measures avoid. Framing growth in terms of doubling times, rather than growth rates, improves understanding. In a non-standard framing, which focuses on time gained rather than cases avoided, the median subject assesses the benefit of mitigation measures correctly. These findings suggest changes that public health authorities can adopt to communicate the exponential spread of infectious disease more effectively. Beyond public health, the findings have applications to, for example, the regulation of the sale of financial products, retirement savings, education and the public understanding of exponential processes in the environment.