Knowledge that Transforms

We combine data on trade, production, and input use to document changes in the value-added content of trade between 1970 and 2009. The ratio of value-added to gross exports fell by roughly 10 percentage points worldwide. The ratio declined 20 percentage points in manufacturing, but rose in nonmanufacturing sectors. Declines also differ across countries and trade partners: they are larger for fast-growing countries, for nearby trade partners, and among partners that adopt regional trade agreements. Using a multisector structural gravity model with input-output linkages, we show that changes in trade frictions play a dominant role in explaining all these facts.

We exploit historical data on planned highways, railroads, and exploration routes as sources of exogenous variation in order to estimate the effect of interstate highways on regional innovation: a 10% increase in a region's stock of highways causes a 1.7% increase in regional patenting over a five-year period. In terms of the mechanism, we report evidence that roads facilitate local knowledge flows, increasing the likelihood that innovators access knowledge inputs from local but more distant neighbors. Thus, transportation infrastructure may spur regional growth above and beyond the more commonly discussed agglomeration economies predicated on an inflow of new workers.

This paper studies the relationship between public debt expansion and economic growth and investigates whether the debt-growth relation varies with the level of indebtedness. We contribute theoretically by developing tests for threshold effects in the context of dynamic heterogeneous panel data models with cross-sectionally dependent errors. In the empirical application, using data on a sample of forty countries over the 1965–2010 period, we find no evidence for a universally applicable threshold effect in the relationship between public debt and economic growth. Regardless of the threshold, however, we find significant negative effects of public debt buildup on output growth.

We argue that a more individualist culture leads to more innovation and to higher growth because of the social status rewards associated with innovation in that culture. We use data on the frequency of particular genes associated with collectivist cultures, as well as a measure of distance in terms of frequencies of blood types, and historic prevalence of pathogens to instrument individualism scores. The relationship between individualism and innovation/growth remains strong even after controlling for institutions and other potentially confounding factors. We also provide evidence consistent with two-way causality between culture and institutions.

We investigate how urban railroad and highway configurations have influenced urban form in Chinese cities since 1990. Each radial highway displaces 4% of central city population to surrounding regions, and ring roads displace about an additional 20%, with stronger effects in the richer coastal and central regions. Each radial railroad reduces central city industrial GDP by about 20%, with ring roads displacing an additional 50%. We provide evidence that radial highways decentralize service sector activity, radial railroads decentralize industrial activity, and ring roads decentralize both. Historical transportation infrastructure provides identifying variation in more recent measures of infrastructure.