||Much aggregate social-science analysis relies upon the standard national income and product accounts as a source of economic data. These are recognized to be defective in many poor countries, and are missing at the regional level for large parts of the world. Using updated luminosity (or nighttime lights) data, the present study examines whether such data contain useful information for estimating national and regional incomes and output. The bootstrap method is used for estimating the statistical precision of the estimates of the contribution of the lights proxy. We conclude that there may be substantial cross-sectional information in lights data for countries with low-quality statistical systems. However, lights data provide very little additional information for countries with high-quality data wherever standard data are available. The largest statistical concerns arise from uncertainties about the precision of standard national accounts data.