Alternative hypotheses and the volume of trade: the gravity equation and the extent of specialization

Abstract.  We examine why the gravity equation works and the implications for its use. First, we demonstrate that the gravity equation as a statistical relationship can be generated from a model with incomplete specialization and trade costs. Second, we analyse the predominance of zero bilateral trade values as a 'puzzle' broadly inconsistent with the complete specialization models typically used to derive the gravity equation, but consistent with the alternative hypothesis of incomplete specialization. Third, we demonstrate that the explanation for why the gravity equation works has considerable relevance for how the gravity equation is interpreted and used and how we view bilateral trade.     

Further Evidence on PPP Adjustment Speeds: the Case of Effective Real Exchange Rates and the EMS*

Two different approaches intend to resolve the ‘puzzling’ slow convergence to purchasing power parity (PPP) reported in the literature [see Rogoff (1996) , Journal of Economic Literature, Vol. 34.] On the one hand, there are models that consider a non‐linear adjustment of real exchange rate to PPP induced by transaction costs. Such costs imply the presence of a certain transaction band where adjustment is too costly to be undertaken. On the other hand, there are models that relax the ‘classical’ PPP assumption of constant equilibrium real exchange rates. A prominent theory put together by Balassa (1964, Journal of Political Economy, Vol. 72) and Samuelson (1964 Review of Economics and Statistics, Vol. 46) , the BS effect, suggests that a non‐constant real exchange rate equilibrium is induced by different productivity growth rates between countries. This paper reconciles those two approaches by considering an exponential smooth transition‐in‐deviation non‐linear adjustment mechanism towards non‐constant equilibrium real exchange rates within the EMS (European Monetary System) and effective rates. The equilibrium is proxied, in a theoretically appealing manner, using deterministic trends and the relative price of non‐tradables to proxy for BS effects. The empirical results provide further support for the hypothesis that real exchange rates are well described by symmetric, nonlinear processes. Furthermore, the half‐life of shocks in such models is found to be dramatically shorter than that obtained in linear models.     

The evolution of a local R&D strategy: the experience of a service in the UK National Health Service (NHS)

Increasing concern about the state of health‐related research in the UK in the 80s and early 90s, led to an influential parliamentary review. The consequence of this was to strengthen health research through a programme that was fully integrated into the management structure of the NHS. No country had ever attempted such an ambitious approach ( Black, 1997 ). In 1994 a far‐reaching review, recommended further, revolutionary changes to the management of R&D in the UK National Health Service ( Culyer, 1994 ). Many of these were implemented in 1997 with the result that every UK health service at regional and local level has developed an infrastructure, and management arrangements for R&D activity. In most local areas, hospitals with significant involvement in R&D have been eligible to bid to the UK Department of Health for NHS R&D Support funds. In Nottingham, three Hospital Trusts and a community based service made bids to the Department of Health and received grants to support R&D. This paper focuses on one of the hospital Trusts ‐ the mental health service in Nottingham. Our experience will be of particular interest as the first bid that the mental health service made was spectacularly unsuccessful. The organisation was forced to consider dis‐investment in its existing research infrastructure and a potential negative impact on the provision of patient care. This led to a wide‐ranging consultation and evaluation of research and research‐related activity. A range of approaches and tools were deployed to develop the strategy and to ensure its successful implementation and evolution. The strategy reflected a balanced approach, taking into account historical and organisational research strengths, while recognising the need to build capacity and capability, enhance foresight capability and strengthen the knowledge base. The ability to contribute to, and influence policy and practice has been a key driver of the strategy. The result was a successful bid and the evolution of an R&D strategy that has been flexible in its response to policy changes, changing local circumstances and wider socio‐economic trends and technical innovations. Furthermore, R&D performance, measured through outputs, impacts and income, has continually improved and increased.     

Non‐linear Predictability of UK Stock Market Returns*

Linear predictability of stock market returns has been widely reported. However, recently developed theoretical research has suggested that due to the interaction of noise and arbitrage traders, stock returns are inherently non‐linear, whereby market dynamics differ between small and large returns. This paper examines whether an exponential smooth transition threshold model, which is capable of capturing this non‐linear behaviour, can provide a better characterization of UK stock market returns than either a linear model or an alternate non‐linear model. The results of both in‐sample and out‐of‐sample specification tests support the exponential smooth transition threshold model and hence the belief that investor behaviour does differ between large and small returns.     

Ill-behaviour of transformation-frontiers with environmental quality versus pollution

If one looks at environmental quality N as a renewable natural resource (with its own natural dynamics) which is changed by emissions Z, then one gets a better understanding of the shape of the damage function. In the case of a logistic growth dynamics one obtains a well-shaped transformation frontier N(Z), even in a two-species natural dynamics. For a more general natural interaction in the framework of a prey-predator model one obtains the possibilities of a cusp catastrophe which makes the transformation frontier N(Z) ill-shaped for the standard arguments of economists and their most favoured environmental policy instruments.     

Buildings for the Japanese information economy : Neighbourhood and resort offices

A new physical infrastructure to support activities based on communications and the transmission of information is being developed. Part of this infrastructure includes the construction of ‘intelligent’ buildings which are seen to play as important a role in improving efficiency of office workers as automation has played on the shopfloor of manufacturing industry. The location of these buildings is important. This article focuses on two types of experimental office development—neighbourhood offices and resort offices.     

A note on incentive incompatibility under franchising

This note provides a formal demonstration of the incentive incompatibility problem that exists in franchisor — franchisee relationships. It is shown that incentive incompatibility exists with respect to both price and quality. Several contractual mechanisms designed to mitigate the incompatibility problem are examined.     

Econometric Cost Structure Estimates for Cellular Telephony in the United States

This article estimates economies of scale for a sample of five cellular telephony firms in the United States. We reject constant returns to scale for all but the smallest firm studied; the remaining firms exhibit decreasing returns to scale. This finding suggests that scale economies cannot be used to justify the current regulated duopoly structure of United States cellular markets.