ONE MAN RULE MEANS JUST THAT: China is conducting fewer local policy experiments under Xi Jinping.

The freedom to tinker has never been unlimited, and various autocratic habits have undermined some experiments. One is secrecy. State media are often ordered to keep quiet about pilot projects in case they go wrong. Results can often be published only in classified journals; leakers face years in jail. If China’s experiments with a less draconian family-planning policy had been debated more openly after their launch in the 1980s, more heed might have been paid to their findings: that it was pointless (as well as cruel) to punish parents for having more than one child. Most wanted small families anyway.

Nonetheless, as in any country, let alone one as vast and varied as China, a suck-it-and-see approach yields better results than deciding everything centrally. Alas, under President Xi Jinping, experimentation of any kind has become harder. In 2010—two years before Mr Xi took over—around 500 policy-related pilot projects were being carried out at the provincial level, reckons Sebastian Heilmann of the University of Trier in Germany. By 2016 the number had dropped to about 70.

One reason is fear.

Xi seems almost determined to kill China’s golden goose.