The impact of malaria on competitiveness depends not only on its incidence rates but also on how costly it is for business. Therefore, in order to estimate the impact, we combine its incidence rate with the Survey question on its perceived cost to businesses. To combine these data we first take the ratio of each country’s disease incidence rate relative to the highest incidence rate in the whole sample. The inverse of this ratio is then multiplied by each country’s score on the related Survey question. This product is then normalized to a 1-to-7 scale. Note that countries with zero reported incidence receive a 7, regardless of their scores on the related Survey question. In the case of malaria, countries receive a 7 if the World Health Organization (WHO) has classified them as malaria-free countries or included them in the supplementary list of areas where malaria has never existed or has disappeared without specific measures.

Source: World Economic Forum