A comparison of additive and multiplicative functions for water poverty index calculation

Abstract

The aim of this research is to quantify the difference in the water poverty index when calculated with the additive function compared to the multiplicative function. It is calculated and compared for the three towns that together form the Vaal Triangle region in South Africa. A case study is performed with data that was collected at the household level, all of which is at a high assurance level. Although many functions are available for the calculation of composite indices, the study finds that although the multiplicative function produced lower overall values, the final recommendation regarding which town is most in need of an intervention would have been unchanged. It concludes that the scale at which the data is gathered, the chosen components, and the data sources could all influence these results, and that the function comparisons are critical in ensuring the relevance of the chosen function. Future research should focus on refining the available functions, as well as on documenting the best functions for different scenarios