VAR FORECASTING USING BAYESIAN VARIABLE SELECTION

This paper develops methods for automatic selection of variables in Bayesian vector autoregressions (VARs) using the Gibbs sampler. In particular, I provide computationally efficient algorithms for stochastic variable selection in generic linear and nonlinear models, as well as models of large dimensions. The performance of the proposed variable selection method is assessed in forecasting three major macroeconomic time series of the UK economy. Data‐based restrictions of VAR coefficients can help improve upon their unrestricted counterparts in forecasting, and in many cases they compare favorably to shrinkage estimators. Copyright © 2011 John Wiley & Sons, Ltd.     

Bank Credit Risk Management and Migration Analysis; Conditioning Transition Matrices on the Stage of the Business Cycle

Credit risk has been one of the most active areas of recent financial research. It is driven by advances in portfolio risk measurement and management techniques, growth in credit derivatives trading, the Basel II implementation, and regulatory concerns stemming from the commercial credit crunch that initially took place in 2001 and 2002 in the USA. Within this broader literature, a growing body of research analyzes the meaning, role, and influence of credit ratings that quantify credit risk. This paper examines the two-way links between credit risk measurement and the macroeconomic conditions, interpreted through phases of business cycles. We propose a methodology applied on bank internal rating data, which estimates ratings migration probabilities while integrating the state of the economy. We first discuss the issue of whether credit risk is low or high in different economic scenarios. In order to evaluate this prospect, we examine each year in four quarters that represent different scenarios throughout the year. We then review how macroeconomic considerations are incorporated into credit risk models and the risk measurement approach that underlies Basel II and Basel III.     

Nonlinear dynamics and the exports–output growth nexus

The untested assumption of a linear relationship between exports and output growth in previous empirical investigations may lead to invalid inference if the actual relationship is nonlinear. This paper re-examines the relationship between exports and economic growth in five industrialized economies (Canada, Italy, Japan, UK, and the US) with emphasis on the effect of nonlinearities on the causal relationships. Results from linearity tests show that nonlinearities do exist in the dynamic relationship between exports and GDP growth. Nonlinear smooth transition autoregressive (STAR) model results suggest that nonlinear Granger causality flows from exports to output growth and vice versa. Predictive accuracy tests further confirm the appropriateness of the nonlinear models over the linear model specification.     

Promoting energy efficiency policies over the information barrier

Stakeholders argue that the information barrier is the major obstacle restricting firms from adopting Energy Efficiency Technologies (EETs) in Europe. The present work examines the processes of information gathering as regards to EETs and explores the factors affecting the level of acquired information by EET adopters. Empirical evidence is provided by a data set of Greek manufacturing firms which have adopted EETs. In conclusion, we propose appropriate policy measures able to promote the adoption of EETs by overcoming the information barrier.     

Productive efficiency and firm exit in the food sector

This work examines the effects of productive efficiency on the survival of firms in the Greek food sector. Technical and scale efficiency scores are computed within a data envelopment analysis (DEA) framework and are used as explanatory variables in a parametric (Weibull) survival model. High technical efficiency increases the median survival time and lowers the hazard rate of exit. As the scale efficiency of a firm operating either at increasing or decreasing returns to scale approaches one (1), its theoretically maximum value, the expected median survival time, is maximized for all types of exits. Developments in biotechnology, the evolution of alternative food supply networks, innovations in the food sector and competition policy are likely to affect technical and scale efficiency of food manufacturing firms. Results unraveling the effects of technical and scale efficiency on the survival of firms in the food sector are of particular relevance to food policy makers.     

Productivity, convergence and policy: a study of OECD countries and industries

This paper analyses trends in labour productivity and its underlying determinants in a panel of OECD countries from 1979 to 2002. Data Envelopment Analysis (DEA) is used to estimate a Malmquist measure of multifactor productivity (MFP) change. We decompose the growth in labour productivity into (i) net technological change (ii) input biased technical change (IBTC) (iii) efficiency change and (iv) capital accumulation. We analyse the effect of each of these factors in the transition towards the equilibrium growth paths of both labour productivity and per capita GDP for the OECD countries, controlling for the effects of different policies and institutions. The results indicate that on average gaps in productivity or income levels are narrowing down although there is no evidence to suggest that the entire OECD area comprises a single convergence “club”. Using kernel estimation methods we find that that labour productivity and per capita GDP are settling toward a twin peak (bimodal) distribution. Panel unit root tests over an extended (1960–2001) period provide general support for the convergence hypothesis. Analysis of the contributions of productivity growth within industries and sectoral composition changes show that aggregate productivity change is predominantly driven by ‘net’ within sector effects with very little contribution emerging from sectoral shifts (the ‘in-between’ static or dynamic effects resulting from higher or above average productivity industries gaining employment shares or low productivity industries losing shares).     

Innovation diffusion with generation substitution effects

Markets of high technology products and services, such as telecommunications, are described by fast technological changes and rapid generational substitutions. Since the conventional modeling approaches that are based on diffusion models do not usually incorporate this important aspect into their formulations, the accuracy of the provided forecasts is consequently affected. The work presented in this paper is concerned with the development of a methodology for describing innovation diffusion, in the context of generation substitution. For this purpose, a dynamic diffusion model is developed and evaluated, based on the assumption that the saturation level of the market does not remain constant throughout the diffusion process but is affected by the diffusion of its descendant generation, as soon as the latter is introduced into the market. In contradiction to the conventional diffusion models, which assume static saturation levels, the proposed approach incorporates the effects of generation substitution and develops a diffusion model with a dynamic ceiling. The importance of such an approach is especially significant for markets characterized by rapid technological and generational changes. Evaluation of the proposed methodology was performed over 2G and 3G historical data and for a number of European countries, providing quite accurate estimation and forecasting results, along with important information regarding the rate of generation substitution.     

Has Greater Stock Market Participation Increased Wealth Inequality in the Us?

Is wider access to stockholding opportunities related to reduced wealth inequality, given that it creates challenges for small and less sophisticated investors? Counterfactual analysis is used to study the influence of changes in the U.S. stockholder pool and economic environment, on the distribution of stock and net household wealth during a period of dramatic increase in stock market participation. We uncover substantial shifts in stockholder pool composition, favoring smaller holdings during the 1990s upswing but larger holdings around the burst of the Internet bubble. We find no evidence that widening access to stocks was associated with reduced net wealth inequality.     

A reassessment of the Feldstein-Horioka hypothesis of perfect capital mobility: evidence from historical data

This short paper explores the relationship between investment and saving rates in a sample of 13 OECD countries over the period 1885–1992. To this end, I employ panel cointegration tests based on the maximum likelihood approach developed by Johansen (J Economic Dynamics Control 12:231–254, 1988) instead of conventional panel cointegration residual based tests, in order to draw sharper conclusions. Using estimation techniques appropriate for heterogeneous panels I find a low degree of capital mobility for the sub-periods 1921–1992 and 1950–1992. The findings overwhelmingly support the hypothesis of perfect capital mobility in the short run.

How forensic scientists learn to investigate cases in practice

The formation of organisational tacit knowledge has been studied in the most part using only qualitative explanations such as case studies including those on the workings of communities of practice. From this perspective, tacit knowledge is submersed and consequently it is difficult to quantify. In our community of communities of practice case study we use quantitative social network analysis techniques to explore the process of tacit knowledge exchange among expert knowledge workers – forensic scientists. Conceptually, we search for more structured relational mechanisms that shape tacit knowledge flows occurring between participant actors in communities of practice, in their day-to-day knowledge intensive environments.