Li Keqiang, who spent a decade as China’s premier and in President Xi Jinping’s shadow, died of a heart attack in Shanghai on Friday, at the age of 68.

It was a sad end for a politician whose career was cut short by a Communist Party power play.

He is best known outside of China for the Li Keqiang Index, created by The Economist to measure the nation’s economic growth. Finding the official gross domestic product number unreliable, Li, a policy wonk, preferred to use high-frequency indicators, such as railway freight traffic, electricity consumption and bank loans, to figure out how well the economy is going.