China's Productivity is Slowing Down

THE growth of China’s economy is staggering: it produced $9.5 trillion-worth of goods and services in 2013, nearly three times more than in 2007. But has that growth come simply from deploying more labour and capital? Or did total factor productivity (TFP)—the efficiency with which those two inputs are used—also increase? China’s future growth hinges on the answer.

A period of high growth does not necessarily involve a rise in productivity. The more people there are in employment, and the more factories and roads there are for them to use, the bigger an economy will be. But those workers and roads may not be put to good use. As long as the amount by which labour and capital grow outpaces any fall in productivity, GDP will still increase.

Growth of this sort, however, can last only so long. Neither labour nor capital are infinite. In the long run, improving the productivity with which they are used is the magic ingredient for any economy, the only path to sustainable growth. Hence the concerns about China. A series of estimates published this year have all suggested that productivity is flagging.

At the pessimistic end of the range is Harry Wu, an economist who has devoted much research to the shortcomings of China’s official economic data. He finds that since 2007 TFP has actually been a drag on the economy, denting growth by about 0.9 percentage points a year. At the more optimistic end, researchers at the World Bank think TFP added nearly three percentage points a year to growth from 2000 to 2010—but even they reckon that is 40% lower than in the 1990s. In between these two estimates are Jianhua Zhang, Chunxia Jiang and Peng Wang, two of whom are with the People’s Bank of China. They conclude that productivity increased just 1.5% a year between 1997 and 2012.

As these diverging estimates suggest, overall productivity growth, despite being central to economics, is frustratingly difficult to pin down. It cannot, after all, be seen. When comparing two workers with the same job in the same company, it is easy to determine which one produces more. For economies, such apple-to-apple comparisons are not possible. Instead, economists get at TFP by subtracting the change in capital and labour deployed from the change in overall output. The difference (known as the Solow residual, after Robert Solow, the economist who pioneered this method) reflects the contribution of productivity to growth. In this way, the unseen becomes visible.

But the process requires several accounting somersaults. Assumptions are needed about, among other things, the size of the capital stock, the rate of capital depreciation and the level of workers’ education. Mr Wu does not trust official GDP figures and so constructs his own. Because his estimate of average annual growth for 2008-12 (6.5%) is dramatically lower than the official figure (9.3%), his calculations yield a negative Solow residual. Productivity, in other words, appears to have gone into reverse.

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