Illuminating GDP

Money and Banking: “GDP figures are ‘man-made’ and therefore unreliable,” reported remarks of Li Keqiang (then Communist Party secretary of the northeastern Chinese province of Liaoning), March 12, 2007.

Satellites are great. It is hard to imagine living without them. GPS navigation is just the tip of the iceberg. Taking advantage of the immense amounts of information collected over decades, scientists have been using satellite imagery to study a broad array of questions, ranging from agricultural land use to the impact of climate change to the geographic constraints on cities (see here for a recent survey).

One of the most well-known economic applications of satellite imagery is to use night-time illumination to enhance the accuracy of various reported measures of economic activity. For example, national statisticians in countries with poor information collection systems can employ information from satellites to improve the quality of their nationwide economic data (see here). Even where governments have relatively high-quality statistics at a national level, it remains difficult and costly to determine local or regional levels of activity. For example, while production may occur in one jurisdiction, the income generated may be reported in another. At a sufficiently high resolution, satellite tracking of night-time light emissions can help address this question (see here).

But satellite imagery is not just an additional source of information on economic activity, it is also a neutral one that is less prone to manipulation than standard accounting data. This makes it is possible to use information on night-time light to monitor the accuracy of official statistics. And, as we suggest later, the willingness of observers to apply a “satellite correction” could nudge countries to improve their own data reporting systems in line with recognized international standards.

As Luis Martínez inquires in his recent paper, should we trust autocrats’ estimates of GDP? Even in relatively democratic countries, there are prominent examples of statistical manipulation (recall the cases of Greek sovereign debt in 2009 and Argentine inflation in 2014). In the absence of democratic checks on the authorities, Martínez finds even greater tendencies to distort the numbers….(More)”.