We present a general equilibrium model of the decisions of firms to innovate and to engage in international trade. We use the model to analyze the impact of a reduction in international trade costs on firms ’ process and product innovative activity. We first show analytically that if all firms export with equal intensity, then a reduction in international trade costs has no impact at all, in steady-state, on firms ’ investments in process innovation. We then show that if only a subset of firms export, a decline in marginal trade costs raises process innovation in exporting firms relative to that of non-exporting firms. This reallocation of process innovation reinforces existing patterns of comparative advantage, and leads to an amplified response of trade volumes and output over time. In a quantitative version of the model, we show that the increase in process innovation is largely offset by a decline in product innovation. We find that, even if process innovation is very elastic and leads to a large dynamic response of trade, output, consumption, and the firm size distribution, the dynamic welfare gains are very similar to those in a model with inelastic process innovation

This paper studies the persistence of innovation in Dutch manufacturing using an unbalanced panel of firm data from four waves of the Community Innovation Survey between 1994 and 2002. We estimate by maximum likelihood a dynamic type 2 tobit model accounting for individual effects and handling the initial conditions problem. We find true persistence in the probability of innovating in the high-tech category of industries and spurious persistence in the low-tech category. Furthermore, past innovation output intensity affects, albeit to a small extent, current innovation output intensity in the high-tech category, while no such evidence is found in the low-tech category

In this paper, I ask the question: Does the output-mix of countries change in response to changes in factor endowments? If so: How long does it take? Using data on capital, as well as skilled and unskilled labour employed in three-digit International Standard Industrial Classification (ISIC) manufacturing industries for a sample of 27 developing and developed countries over the 1973–1990 period, I find that the output-mix of countries does not change in response to endowment changes, even after 15 years. This answer raises another question: How then do countries absorb changes in factor endowments? The data show that in both the short and long runs, an increase in the supply of a production factor reduces its rate of return and makes it more intensively used in all sectors of the economy: changes in production techniques. In the long run, the point estimate is that the reduction in the rate of return is more than 50% larger than in the short run. This is consistent with induced innovations being predominantly biased towards the scarce factor

This paper studies whether labor scarcity encourages technological advances, that is, technology adoption or innovation, for example, as claimed by Habakkuk in the context of nineteenth-century United States. I define technology as strongly labor saving if technological advances reduce the marginal product of labor and as strongly labor complementary if they increase it. I show that labor scarcity encourages technological advances if technology is strongly labor saving and will discourage them if technology is strongly labor complementary. I also show that technology can be strongly labor saving in plausible environments but not in many canonical macroeconomic models

The Public and Private Sectors in the Process of Innovation: Theory and Evidence from the Mouse Genetics Revolution by Philippe Aghion, Mathias Dewatripont, Julian Kolev, Fiona Murray and Scott Stern. Published in volume 100, issue 2, pages 153-58 of American Economic Review, May 2010

An unsustainable weakening of credit standards induced a US mortgage lending and housing bubble, whose consumption impact was amplified by innovations altering the collateral role of housing. In countries with more stable credit standards, any overshooting of construction and house prices owed more to traditional housing supply and demand factors. Housing collateral effects on consumption also varied, depending on the liquidity of housing wealth. Lessons for the future include recognizing the importance of financial innovation, regulation, housing policies, and global financial imbalances for fueling credit, construction, house price and consumption cycles that vary across countries

Great achievements in knowledge are produced by older innovators today than they were a century ago. Nobel Prize winners and great inventors have become especially unproductive at younger ages. Meanwhile, the early life cycle decline is not offset by increased productivity beyond middle age. The early life cycle dynamics are closely related to age when the PhD was received, and I discuss a theory where knowledge accumulation across generations leads innovators to seek more education over time. More generally, the narrowing innovative life cycle reduces, other things equal, aggregate creative output. This productivity drop is particularly acute if innovators' raw ability is greatest when young

Every now and then a set of technologies becomes available that sets off a period of “combinatorial innovation. ” Think of standardized mechanical parts in the 1800s, the gasoline engine in the early 1900s, electronics in the 1920s, integrated circuits in the 1970s, and the internet in the last decade or so. The component parts of these technologies can be combined and recombined by innovators to create new devices and applications. Since these innovators are working in parallel with similar components, it is common to see simultaneous invention. There are many well-known examples, such as the electric light, the airplane, the automobile, and the telephone. Many scholars have described such periods of innovation, using terms such as “recombinant growth, ” “general purpose technologies, ” “cumulative synthesis” and “clusters of innovation. ” 1 The internet and the web are wonderful examples of combinatorial innovation. In the last 15 years we have seen a huge proliferation of web applications, all built from a basic set of component technologies. The internet itself was a rather unlikely innovation; I like to describe it as a “lab experiment that got loose. ” Since the internet arose from the research community rather than the private sector, it had no obvious business model. Other public computer networks, such as AOL, CompuServe, and Minitel, generally used a subscription models, but were centrally controlled and offered little scope for innovation at the user level. The internet won out over these alternatives, precisely because it offered a flexible set of component technologies which encouraged combinatorial innovation

We explore the effects of fat tails on the equilibrium implications of the long-run risks model of asset pricing by introducing innovations with dampened power law to consumption and dividends growth processes. We estimate the model structural parameters by maximum likelihood. We find that the stochastic volatility model with fat tails can generate implied risk premium, expected risk free rate and their volatilities comparable to the magnitudes observed in data. The model with fat tails leads to a significant increase in implied risk premia over the benchmark Gaussian model, but similar values for other equilibrium quantities of interest

In a financial system in which balance sheets are continuously marked to market, asset price changes appear immediately as changes in net worth, and eliciting responses from financial intermediaries who adjust the size of their balance sheets. We document evidence that marked-to-market leverage is strongly procyclical. Such behavior has aggregate consequences. Changes in dealer repos – the primary margin of adjustment for the aggregate balance sheets of intermediaries – forecast changes in financial market risk as measured by the innovations in the Chicago Board Options Exchange Volatility Index VIX index. Aggregate liquidity can be seen as the rate of change of the aggregate balance sheet of the financial intermediaries