For more than a decade, China has accounted for a quarter or more of global economic growth. With its economy currently navigating a rough patch, the question is whether this impressive performance will persist.

Cassandras pointing to the possibility of a Chinese growth slowdown regularly invoke the specter of a middle-income trap. Now that China is no longer poor, they warn, growth rates will fall, just as they have in all but a handful countries that have reached the same income level.

Growth is harder, they observe, when it can no longer be based on brute-force capital accumulation. Now, it must be based on innovation, which is difficult to bring about in an economy that is still centrally directed.