Bayesian modelling of catch in a north-west Atlantic fishery

Summary. We model daily catches of fishing boats in the Grand Bank fishing grounds. We use data on catches per species for a number of vessels collected by the European Union in the context of the Northwest Atlantic Fisheries Organization. Many variables can be thought to influence the amount caught: a number of ship characteristics (such as the size of the ship, the fishing technique used and the mesh size of the nets) are obvious candidates, but one can also consider the season or the actual location of the catch. Our database leads to 28 possible regressors (arising from six continuous variables and four categorical variables, whose 22 levels are treated separately), resulting in a set of 177 million possible linear regression models for the log-catch. Zero observations are modelled separately through a probit model. Inference is based on Bayesian model averaging, using a Markov chain Monte Carlo approach. Particular attention is paid to the prediction of catches for single and aggregated ships.     

Discussion of “Nonparametric Bayesian Inference in Applications”: Bayesian nonparametric methods in econometrics

The use of Bayesian nonparametrics models has increased rapidly over the last few decades driven by increasing computational power and the development of efficient Markov chain Monte Carlo algorithms. We review some applications of these models in economic applications including: volatility modelling (using both stochastic volatility models and GARCH-type models) with Dirichlet process mixture models, uses in portfolio allocation problems, long memory models with flexible forms of time-dependence, flexible extension of the dynamic Nelson-Siegel model for interest rate yields and multivariate time series models used in macroeconometrics.     

Resources and strategies of interest groups and industry representatives involved in federal forest policy

This study analyzes the resources and strategies of public interest groups and industry representatives involved in federal forest policy in the state of Oregon during the early 1990s. While many studies have examined the role of interest groups in the policy process, few have compared empirically the resources available and strategies pursued by industry representatives and public interest groups in a particular policy domain. Utilizing survey data from 133 business representatives and 326 public interest groups involved in federal forest policy, the study argues that public interest group influence derives primarily from the ability to mobilize human resources; the financial resources of these groups tend to be modest. Industry and industry-supported groups, in contrast, possess considerable financial power while enjoying less support from the public. Consequently, industry interests tend to focus their efforts on more traditional forms of influence such as the persistent lobbying of natural resource agencies and elected officials. Public interest groups, in contrast, tend to devote considerable efforts to building public support in urban core areas to build the capacity to pressure governmental decision-makers.     

Exclusion restrictions in instrumental variables equations

In this paper we consider two-stage estimators of parameters of a structural equation in a model with recursive exclusion restrictions on the instrumental variables equations. The estimations considered are simple OLS and GLS estimators after substitution of estimates of the systematic part of the IV equations for the endogenous variables. It is known in the literature that neither imposing the restrictions in the first stage nor ignoring them will in general be more efficient than the alternative. We introduce a class of mixed instrumental variables estimators (MIV) with these possibilities as special cases which yields an estimator which is not only more efficient than the two stage estimators considered in the literature but as efficient as an efficient system estimator like 3SLS.     

Personality Disorders Among Pathological Gamblers

The objective of this study was to investigate the prevalence of DSM-III-R diagnostic categories of personality disorders in pathological gamblers and to highlight the possible association between such disorders, psychological distress and selected forms of gambling. The Personality Disorders Questionnaire-Revised and a battery of psychometric measures were administered to a sample of 82 consecutive admissions to a behavioral treatment program for gambling problems at an impulse control disorders research unit in Sydney, Australia. Seventy-three percent of subjects were male. The total sample reported having gambled a mean of 15 years of which, on average, the last 6.4 years were associated with problems. Results indicated that the majority of subjects met diagnostic criteria for at least one Personality Disorder (93%), with an average of 4.6 personality disorders per subject. The majority of gamblers evidenced personality disorders from the Cluster B grouping with particularly high rates of borderline, histrionic, and narcissistic personality disorders which were found to be associated with high levels of impulsivity and affective instability. Antisocial personality disorder and narcissistic personality disorder were both found to be possible mediators of the severity of the problem gambling behaviours.     

Which countries protect intellectual property? The case of software piracy

Using data on software piracy, we examine how protection of intellectual property varies across countries. Consistent with other studies, we find that intellectual property receives greater protection in developed economies; high-income countries have lower piracy rates. We also find that protection depends on cultural factors. Countries with an individualist culture have lower piracy rates than do countries with a collectivist culture. Piracy rates are also lower in countries that have strong institutions that enforce contracts and protect property from expropriation. These results suggest that national policies toward intellectual property reflect not only economic concerns but also national culture and institutions.     

NGOS AND THE DEVELOPMENT OF CIVIL SOCIETY IN BULGARIA AND THE USA

This study examines the development of civil society and its ability to facilitate stronger democratic practices in Bulgaria using the USA as a comparison. Using data gathered from surveys of NGOs in 2006, we examine three sets of questions. First, what is the level of NGO organizational capacity? Second, to what degree are NGOs performing their mediating roles? Third, how do NGOs perceive their effectiveness in working with the state and its citizens. Our findings suggest that Bulgarian NGOs face a number of challenges when compared with US NGOs, which affect their ability to engage in civil society activities such as establishing horizontal ties with citizens and other groups.