Comments and Discussion
评论了一篇关于中国资本回报率的研究，指出其回报率仍高（约20%），并讨论了资本份额高企及全要素生产率增长放缓的疑点，适合关注中国经济增长的学者。
Comments and Discussion Olivier Blanchard and Richard N. Cooper Olivier Blanchard: This is a very useful paper. There is a widely held belief that the return to capital in China is low, driven down by an investment rate in excess of 40 percent of GDP. The paper looks at the data carefully and concludes that this is not the case: the rate of return decreased in the 1990s but is now stable, yet still high, at roughly 20 percent. The approach of the paper is straightforward. Simplifying a bit: it defines the rate of return to capital as the ratio of profit to the value of the capital stock, minus the depreciation rate: It then rewrites his expression as where α is the share of capital in output. Turning to the data, the authors find that the ratio of the value of capital to the value of output is relatively low in China, and the share of capital in output is relatively high. Together these two findings imply a high rate of return on capital. In 2005, for example, the capital-output ratio was 1.72, the share of capital was 58 percent, and the depreciation rate was 10 percent, implying a rate of return of 24 percent. This ignores the impact of the relative growth rates of capital and output prices, which I have left out of the definition above but is (correctly) included in the authors' computation. [End Page 89] Do the computations leave room for disagreement? The authors clearly do as careful an empirical job as one can, given the somewhat unreliable data. Still, the high value of the capital share is striking, about 15 to 20 percentage points above values in other countries at similar levels of development.1 To those of us who (for no good reason) like to think of production largely in Cobb-Douglas terms, such a dramatic difference in capital shares is puzzling. Thus, for the presentation of the paper at the Brookings conference, I tried my best to come up with various stories for measurement error, from the misallocation of self-employment income to the different incentives for township and village enterprises, state-owned firms, or multinationals to misstate profits. In this final draft the authors have done a great job of maiming if not killing most of my tentative hypotheses. However, I still want to take up two issues. The first is that of self-employment. In most low- and middle-income countries, the reported capital share is indeed very high, often above 0.6. But, as is well understood, a large part of what is classified as capital revenue is in fact self-employment income, much of which should be counted as labor income. When Douglas Gollin makes this adjustment, the resulting capital share drops, often by more than 20 percentage points.2 I suspected that the same was likely to be true in China. It turns out, however, that until 2005 the Chinese statistical authorities classified all self-employment income as labor income. In other words, if anything, the reported capital share understated true capital income, at least until 2005. I must admit that I am stumped; all I can do is be a bad loser and suggest that someone look over the shoulders of the Chinese statistical authorities to see how the statistics are put together. The second issue is the implication of the reported capital share for another standard exercise, namely, the computation of total factor productivity growth. My table 1 summarizes the conclusions from a number of studies, which differ on a number of empirical dimensions but typically use capital shares for the construction of the Solow residual roughly similar to those used in this paper. The general pattern is that of a decrease in measured TFP growth over time, with very slow growth in recent years. That true TFP growth would have slowed in China in recent years is, on the face of it, implausible. State firms are being restructured. Foreign direct [End Page 90] investment has been very high, and we know from a number of studies that foreign firms in China, or joint ventures including foreign firms, have higher productivity than domestic firms...