Using remotely sensed night-time light as a proxy for poverty in Africa

Area of Science:

• Geospatial analysis
• Public health
• Socioeconomic indicators

Background:

• Population health is intrinsically linked to poverty.
• Monitoring health indicators across poverty levels is crucial for intervention assessment.
• Existing poverty measures are costly and difficult to compare globally.

Purpose of the Study:

• To evaluate the utility of remotely sensed night time lights (NTL) as a poverty metric in Africa.
• To compare NTL data with traditional asset-based poverty indices.
• To explore NTL's potential for sub-national health equity research.

Main Methods:

• Principal component analysis computed asset-based poverty indices from survey data (Administrative 1 level, 37 African countries).
• Geographical information systems derived NTL metrics (mean brightness, distance, area coverage).
• Correlations and agreement between NTL metrics and asset indices were analyzed.

Main Results:

• NTL metrics effectively distinguished between the poorest and wealthiest population quintiles.
• Mean NTL brightness showed the highest correlation with asset-based wealth indices (continuous and ordinal forms).
• High statistical significance (p < 0.01) and agreement (Kappa = 0.64) were observed.

Conclusions:

• NTL brightness provides a robust, cost-effective alternative to survey-derived poverty indices in Africa.
• NTL data can facilitate the study of economic disparities in health outcomes and intervention access.
• This approach is valuable for sub-national analysis where detailed asset data is unavailable.