Issues in the estimation and application of latent structure models of choice

Our paper provides a brief review and summary of issues and advances in the use of latent structure and other finite mixture models in the analysis of choice data. Focus is directed to three primary areas: (1) estimation and computational issues, (2) specification and interpretation issues, and (3) future research issues. We comment on what latent structure models have promised, what has been, to date, delivered, and what we should look forward to in the future.     

Australian Audit Committees — Do They Meet Best Practice Guidelines?

The paper reports the results of a study of Australia's largest 250 companies' audit committees in two years (1998 and 2001). The audit committees were scrutinised on the bases of audit committee independence and the frequency of meetings. Australia's audit committees did not score highly on either criterion and most companies fell short of best practice guidelines. Further, it was puzzling and of concern that Australian audit committees appear to have deteriorated in terms of independence and frequency of meetings between 1998 and 2001.     

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.     

Wage and price controls in the equilibrium sequential search model

In this paper, we study the effects of wage and price controls on employment, output, and welfare in a simplified version of the Bénabou (J. Econom. Theory 60 (1993) 140) equilibrium sequential search model with bilateral heterogeneity. We show that a price ceiling increases output but the change in welfare depends on three effects: the reduction in aggregate search costs, the increase in surplus due to increased output, and the transfer of production to the least efficient firm. The model is formally identical to a standard equilibrium search model of the labor market so analogous results hold for the minimum wage.     

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.