以前、共著論文およびINETインタビュー記事を紹介したServaas Stormが、「The New Normal」と題したINETブログ記事を執筆している(H/T Economist's View)。


Potential growth is exogenous if one assumes, as is commonly done, that the alarming crisis of U.S. productivity growth crisis is exclusively due to supply-side factors such as excessive (labor market) regulation, undue business taxes, an insufficiently skilled labor force, and too little competition (also from abroad). Demand does not matter in the long run and hence the TFP growth crisis cannot be lastingly cured by fiscal stimulus (as Trump seems to propose), higher real wages, or a restructuring of the private debt overhang. In this view, because demand is side-lined, rising inequality, growing polarization and the vanishing middle class play no role whatsoever as drivers of slow potential growth. They simply drop out of the story. I think this is wrong.


The U.S. economy is suffering from two interrelated diseases: the secular stagnation of its potential growth, and the polarization of jobs and incomes. The two disorders have a common root in the demand shortfall, originating from the ‘unbalanced’ growth between technologically ‘dynamic’ and ‘stagnant’ sectors, which—crucially—is bringing down potential growth. To understand how the short-run demand shortfall carries over into the long run, we must first rethink the Solow residual, which economic textbooks define as the best available measure of the underlying pace of exogenous innovation and Hicks-neutral technological change (Furman 2015). But it can be shown, using national-income accounting, that there is no such thing as a Solow residual, because it must equal—as a matter of accounting identity—either ‘weighted-factor-payments’ growth or ‘weighted-factor-productivities’ growth. My empirical analysis using BEA data for the period 1948-2015 shows that this is the case, bringing out that the secular decline in aggregate U.S. TFP growth is due primarily to secular declines in aggregate real wage growth and aggregate labor productivity growth.

次いで彼は、Ryan Aventの生産性のパラドックス論ピーター・テミンの二重経済論を結び付けたような主張を展開している。

The question is what causes these. I argue in a new working paper that on both theoretical and empirical grounds that the suppression of U.S. real wage growth—what Alan Greenspan called the “atypical restraint on compensation increases [that] has been evident for a few years now and appears to be mainly the consequence of greater worker insecurity”—has been the main driver of faltering labor productivity growth and hence of TFP growth as well. This influence of wage growth on productivity growth can be alternatively explained as ‘induced technical change’, ‘Marx-biased technical change’, or ‘directed technical change’—but the key mechanism is just this: rising real wages, as during the period 1948-1972, provide an incentive for firms to invest in labor-saving machinery and productivity growth will surge as a result; but when labor is cheap, as during most of the period 1972-2015, businesses have little incentive to invest in the modernization of their capital stock and productivity growth falters as a consequence (Storm and Naastepad 2012). Globalization enabled the establishment of this low-wage-growth regime, in combination with domestic labor market deregulation and de-unionization. Financial globalization, in addition, enabled the rich to have their cake (profits) and eat it (by channeling them to offshore tax havens or into derivative financial instruments). In this way, trade and financial globalization have been essential building blocks of the dual economy (Temin 2017).


But the story so far is by no means complete. My growth accounting analysis for the U.S. economy during 1948-2015 shows that the slowdown in aggregate productivity growth is hiding from view a growing divergence in productivity performance and technological zing between a ‘dynamic’ sector (which includes ‘Manufacturing’, ‘Information’, FIRE and ‘Professional Business Services’) and a ‘stagnant’ sector (which includes ‘Utilities & Construction’, ‘Educational, Health & Private Social Services’ and the ‘Rest’, made up of fast-food services, arts & entertainment, recreational and other services).
The growing segmentation suggests a Baumol-like pattern of ‘unbalanced growth’ between a technologically ‘dynamic’ sector, which is shedding jobs and workers, and a ‘stagnant’ and ‘survivalist’ sector which acts as an ‘employer of last resort’. The growing segmentation between these sectors leads to a structural shortfall of aggregate demand, as workers shift from higher-paid dynamic to lower-paid stagnant activities, and this employment shift depresses labor productivity and real wage growth in stagnant activities. Demand growth, when lowered over a long enough period of time, starts to depress dynamic-sector productivity growth as well, hence aggregate potential growth comes down. Unbalanced growth causes premature stagnation.
Following this logic, the intentional creation of a structurally low-wage-growth economy, post 1980, has not just kept inflation and interest rates low and led to workers ‘traumatized by job insecurity’ (in Greenspan’s words) accepting ‘mediocre jobs’ in the stagnant sector—it has also slowed down capital deepening, the further division of labor, and the rate of labor-saving technical progress in the dynamic core. Hence, through the well-known Kaldor-Verdoorn effect, productivity growth in the dynamic sector has been depressed as well (see Basu & Foley 2013 for evidence for the U.S. on this relation).


Their mistake is to lopsidedly assume that potential output growth is determined by the inexorably exogenous factors of ‘technology’ and ‘demography’, while demand growth is simply irrelevant in the long run. It is high time to write off the intellectual sunk capital invested in this—mistaken—belief—if only because on present dualizing trends the U.S. economy cannot preserve its social and political legitimacy for long.


*2:cf. これ


Macroeconomics Beyond the NAIRU

Macroeconomics Beyond the NAIRU

*4:cf. ここFIRE economy - Wikipedia

*5:cf. 下記の本の一節

グリーンスパン (日経ビジネス人文庫)

グリーンスパン (日経ビジネス人文庫)