Technological and geographical proximity effects on knowledge spillovers: evidence from the US patent citations

The purpose of this paper is to investigate the pattern of knowledge flows as indicated by the patent citations in three areas: USA, Japan and Europe. In each economic area, we use information from United States Patent and Trademarks Office data to assess empirically the impact of the technological and geographical proximities for 530 international firms. In particular, the contribution to the existing literature is twofold: first, we use an international sample in such a way that we may compare the empirical results among different economic markets; second, we extend the analysis of the determinants of knowledge spillovers, taking into account the time dimension of the effects of the proximities. In order to compute the technological proximity, we follow the methodology developed by A.B. Jaffe (1986 Jaffe, A. B. 1986. Technological opportunity and spillovers of R&D: Evidence from firms’ patents, profits and market value. American Economic Review, 76(5): 984–1001. [Web of Science ®] , [Google Scholar]. Technological opportunity and spillovers of R&D: Evidence from firms’ patents, profits and market value. American Economic Review 76, no. 5: 984–1001), where a technological vector is based on the distribution of patents of each firm across technology classes. As far as the geographic proximity is concerned, we use the latitude and the longitude coordinates of the city in which each firm is situated to obtain the distance, in miles, between the firms. The empirical results, in line with results from previous studies, indicate that there is a statistically significant relationship between the knowledge flows, proxied by the patent citations, and the proximities, but the effects are rather differentiated according to the proximity type.     

Knowledge technological proximity: evidence from US and European patents

The purpose of this paper is to explore the correlation between the technological proximity measures in three areas: USA, Japan and the Europe. In each economic area, we use information from two international patent systems to construct the technological proximity for 240 large international firms. In particular, we select firms’ patents from United States Patent and Trademarks Office data and European Patent Office data. In order to compute the technological proximity, we follow the methodology developed by Jaffe [1986. “Technological Opportunity and Spillovers of R&D: Evidence from Firms’ Patents, Profits and Market Value.” American Economic Review 76 (5): 984–1001], where a technological vector is based on the distribution of patents of each firm across technology classes. Since the Jaffe distance assumes that spillovers only occur within the same technology class, but rules out spillovers between different classes, we develop also a distance measure which exploits the Mahalanobis norm to identify the distance between different technology classes based on the frequency that patents are taken out in different classes by the same firm. The contribution to the existing literature is to investigate the robustness of the technological proximity measure and the extent to which it may be affected by patent system features.     

Do central banks act asymmetrically? Empirical evidence from the ECB and the Bank of England

The paper attempts to exploit whether monetary authorities have a different behaviour during recession and expansion. To this end, a multivariate extension of Hamilton Markov-switching model is adopted. First, regime dependent Taylor-type rules are estimated for the Euro Area and the United Kingdom in order to capture the systematic behaviour of central banks. Then, impulse response functions that account for the different phases of the business cycle are analysed. In addition, a comparative analysis concerning the estimated rules as well as the different reaction of real economy to monetary shocks is implemented. The study strongly suggests that central banks cannot neglect the regime where the monetary action takes place. It follows that the phase of business cycle is an important matter in monetary policy decision process.     

Geographic labour mobility and the cost of housing: evidence from Italy

In recent years, internal migration in Italy has declined markedly, notwithstanding the widening of the North-South gap in terms of unemployment rates and real income. Here, the extent to which the housing market has contributed to the decline is examined. Preliminary to this analysis, differentials in the cost of housing between the macro-areas of the country are estimated using data on the market price of houses located in 96 provincial capitals. Econometric evidence is provided supporting the view that the North-South housing price differential is a notable factor in explaining the falling pattern of mobility. The positive impact on migration from the South to the North of a wider gap in the two areas in terms of income and employment prospects has been offset by the housing price differential, which has steadily risen at least from the mid-1980s onwards. Yet, a considerable share of the decrease in mobility remains unexplained, possibly owing to the heterogeneity in the composition of migration flows across different cohorts.     

Un modello non lineare sul funzionamento dei mercati azionari

Si analizza il funzionamento di un mercato azionario dove gli agenti sono caratterizzati da razionalità limitata, comportamento eterogeneo e disponibilità limitata di risorse finanziarie. La dinamica del mercato azionario viene spiegata attraverso un sistema non lineare del secondo ordine, a tempo continuo. Vengono esaminate le biforcazioni verificantesi al variare di un parametro avente particolare significato dal punto di vista finanziario. Ciò consente di rilevare l'esistenza di diverse modalità di funzionamento asintotico. Come suggerito dall'intuizione, al crescere del numero degli agenti dotati di minore razionalità, la dinamica del mercato diviene sempre più irregolare.

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Summary A stock market model is conceived within which investors are qualified by bounded rationality, asymmetric behaviour, and restricted availability of money. The stock market is represented through a second order nonlinear model which is continuous in time. Attention is attached to the bifurcations that arise when a financially meaningful parameter is suitably varied. In this way a range of asymptotic behaviours is detected. As one would expect, an excess in traders with low rationality results in an unstable market.

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Si ringraziano sentitamente il Prof. S. Baldone, il Prof. M. Gatto, il Dott. M. Miari, il Prof. L. Peccati ed il Prof. S. Rinaldi per i preziosi suggerimenti offerti.     

Firm Size Distribution in Small Samples

Sutton (1998) has recently proposed a theoretical lower bound to firm size inequality when a market is made of several independent submarkets. His results are valid asymptotically, as the number of submarkets becomes arbitrarily large. We show that, in small samples, his results can be interpreted as a positive relationship between an index of firm size inequality and the number of submarkets. We also test this relationship in the Italian motor insurance market.     

Background Uncertainty and the Demand for Insurance Against Insurable Risks

Theory suggests that people facing higher uninsurable background risk buy more insurance against other risks that are insurable. This proposition is supported by Italian cross-sectional data. It is shown that the probability of purchasing casualty insurance increases with earnings uncertainty. This finding is consistent with consumer preferences being characterized by decreasing absolute prudence.     

A new turnpike theorem for discounted programs

Summary In this paper we present new results on the local and global convergence property of solutions to an optimization model where the objective function is a discounted sum of stationary one-period utilities. The asymptotic local turnpike is given without differentiability assumptions but imposing some mild curvature restrictions on the utility function. This approach allows us to get easy estimates on the range of discount factors and the size of the neighborhood for which the asymptotic property occurs. The paper concludes by providing two global turnpike theorems. The first one is an asymptotic theorem derived from a result similar to Scheinkman's visit lemma. The second one turns out to be a restatement of McKenzie's neighborhood turnpike theorem.This research was partially supported by MURST, National Group on Nonlinear Dynamics in Economics and Social Sciences.