This study explores the use of nighttime luminosity as a proxy for economic output in developing countries, particularly those with poor statistical systems. The authors compare luminosity data with standard measures of output (GDP) at both the country and grid-cell levels from 1992 to 2008. They find that luminosity can provide valuable information for countries with low-quality statistical systems, especially those without recent population or economic censuses. The study uses a statistical framework to analyze the correlation between luminosity and output, considering measurement errors and the relationship between the two variables. The results show that luminosity adds significant value for countries with the poorest statistical systems (grades D and E), while it has limited value for countries with high-quality data systems (grades A, B, and C). The study also highlights the challenges in estimating output in low-output-density regions due to the low level of stable lights, which can be indistinguishable from background noise. Overall, the findings suggest that nighttime luminosity can be a useful supplement to current economic indicators in regions with poor data quality or missing data.This study explores the use of nighttime luminosity as a proxy for economic output in developing countries, particularly those with poor statistical systems. The authors compare luminosity data with standard measures of output (GDP) at both the country and grid-cell levels from 1992 to 2008. They find that luminosity can provide valuable information for countries with low-quality statistical systems, especially those without recent population or economic censuses. The study uses a statistical framework to analyze the correlation between luminosity and output, considering measurement errors and the relationship between the two variables. The results show that luminosity adds significant value for countries with the poorest statistical systems (grades D and E), while it has limited value for countries with high-quality data systems (grades A, B, and C). The study also highlights the challenges in estimating output in low-output-density regions due to the low level of stable lights, which can be indistinguishable from background noise. Overall, the findings suggest that nighttime luminosity can be a useful supplement to current economic indicators in regions with poor data quality or missing data.