In the world's economic 'black holes,' data still leak out‎

From satellite imagery to clandestine price reports, a new study draws on North Korea to explore economic activity in opaque regimes and information-scarce regions. North Korea is the blackest of economic black holes. Even a basic question like "is the economy shrinking or expanding?" can be difficult to answer. The country does not publish reliable statistics. It sharply restricts outside access and treats trade data as a state secret.