As informal markets and budding entrepreneurs rise to fill more of the void left by failed state-owned enterprises in North Korea, analysts outside the notoriously secretive country are finding it even more tricky to measure its economy.
That is the message from Cho Tae-hyoung, the chief of the North Korea research team at South Korea's central bank in Seoul, which is considered the most authoritative source for estimates on Kim Jong Un's economy.
Cho and his colleagues at the Bank of Korea draw on a grab-bag of hard data, suppositions and guesswork that would bring despair to economists studying most countries.