Blinded by the Light: Monitoring Local Economic Development Over Time With Nightlight Emissions

Abstract

Nighttime light (NTL) emissions are widely used across disciplines to map the spatial distribution of a variety of socio-economic variables. For economic studies, NTLs allow to proxy for levels of economic indicators at the country level as well as the local level. Further, multi-temporal differences in NTL intensity are also related to GDP differences on the country level. In this study, we investigate if this relation in temporal differences also holds for the local level. We test this with DMSP as well as VIIRS NTLs data from 2010-2015 in Nigeria, Tanzania, and Uganda. Even though we successfully map local levels of socio-economic status with NTLs, we find multi-temporal changes in NTLs at this local level to be uncorrelated with socio-economic development over time. We conclude that luminosity values based on current DMSP and VIIRS sensors are no silver bullet in measuring local economic changes over time and should, if at all, only be used with caution for this.