Symmetry and order in the portfolio allocation problem

Summary. This research studies the role of multivariate distribution structures on random asset returns in determining the optimal allocation vector for an expected utility maximizer. All our conclusions pertain for the set of risk averters. By carefully disturbing symmetry in the distribution of the, possibly covarying, returns, we ascertain the ordinal structure of the optimized allocation vector. Rank order of allocations is also established when a permutation symmetric random vector is mapped into the returns vector through location and scale shifts. It is shown that increased dispersion in the vectors of location and scale parameters benefit, ex-ante, investors as does a decrease in the rank correlation coefficient between the location and scale parameter vectors. Revealed preference comparative static results are identified for the location and scale vectors of asset returns. For most issues addressed, we arrive at much stronger inferences when a safe asset is available. Received: August 8, 2000; revised version: January 8, 2001     

Cognitive processing models in performance appraisal: evidence from the Malaysian education system

The effectiveness of the decision‐making process in appraisal has been of long‐standing interest. This paper reports the results of research exploring the extent to which those undertaking appraisals apply systematic processes to their decision‐making, represented in terms of the cognitive processing models applied by appraisers. Results of 22 cognitive mapping interviews exploring appraisal practice, undertaken with appraisers in the Malaysian education system, are described. The resultant cognitive maps have been explored for what they tell us about the cognitive processing models underlying appraisers' decision‐making. Results suggest that the practice of appraisal evidenced in interviews demonstrates the presence of cognitive processing that reflects theoretical cognitive processing models, although some differences are observed between less experienced and experienced appraisers' models. Implications from the interview findings for the practice of appraisal are identified.     

The Effects of Occupational Injuries After Returns to Work: Work Absences and Losses of On-the-Job Productivity

We extend the research on postinjury employment by estimating productivity losses for workers with permanent partial disabilities (PPDs) in the first three years after injury. Our method distinguishes between productivity losses attributed to spells of work absence versus reduced earnings during spells of employment. The method is applied to data for 800 Ontario workers with PPDs. The results document large productivity losses persisting at least three years after injury, with different loss patterns for workers returning to stable versus unstable employment. Human capital investments or job accommodations can reduce productivity losses, but the significant determinants of losses differ for the stable versus unstable employment groups.     

Combining information for prediction in linear regression

This article deals with the prediction problem in linear regression where the measurements are obtained using k different devices or collected from k different independent sources. For the case of k=2, a Graybill-Deal type combined estimtor for the regression parameters is shown to dominate the individual least squares estimators under the covariance criterion. Two predictors ŷ _c and ŷ _p are proposed. ŷ _c is based on a combined estimator of the regression coefficient vector, and ŷ _p is obtained by combining the individual predictors from different models. Prediction mean square errors of both predictors are derived. It is shown that the predictor ŷ _p is better than the individual predictors for k≥2 and the predictor ŷ _c is better than the individual predictors for k=2. Numerical comparison between ŷ _c and ŷ _p shows that the former is superior to the latter for the case k=2.     

CAP Reforms in the 1990s and their Price and Welfare Implications: The Case of Wheat

We use a nonlinear commodity market model to assess, theoretically and empirically, the impacts of recent reforms of the CAP on prices and economic welfare in the EU. The empirical analysis is based on an aggregate structural econometric model of the EU wheat economy and its links to the rest of the world. Instability issues are also investigated. Impacts of CAP reforms on the variance of domestic and world prices are analysed and a Monte Carlo simulation is used to evaluate uncertainty in the model's welfare computations. Recent reforms led to a net welfare gain within the EU during the period 1993–2000. Additional budgetary costs are less than the welfare gains of consumers and producers. Producers gained as lower price support was overcompensated by additional direct payments.     

The Evolution of the Social Contract

Two transitions in the evolution of the social contract are considered, the first from the dominance hierarchies of the great apes (used as a proxy for our prehuman ancestors) to the egalitarian political structure of non-sedentary hunter-gatherer bands, and the second, to the reintroduction of hierarchical institutions of governance, primarily a result of living in fixed settlements after the inception of agriculture. The first transition was a product of biological and cultural evolution, which brought about big brains, language, higher consciousness, and a lower rate of time preference that enabled early man to sustain an egalitarian social contract and thereby escape the domination that confronted his prehuman ancestors. The second transition was a product of cultural evolution alone. The high costs of enforcing the hunter-gatherer social contract caused it to break down and be replaced by hierarchy when the domestication of plants and animals gave rise to a sedentary existence and increased populations. However, it is shown that the very biological and cultural adaptations that made hunter-gatherer egalitarianism possible were a necessary foundation for the spontaneous creation of complex culture and the evolution of institutions that would once again eventually make freedom possible and economic prosperity possible.     

Temporary controls on capital inflows

During the past decade a number of countries imposed capital controls that had two distinguishing features: they were asymmetric, in that they were designed principally to discourage capital inflows, and they were temporary. This paper studies formally the consequences of these policies, calibrates their potential effectiveness, and assesses their welfare implications in an environment in which the level of capital inflows can be sub-optimal. In addition, motivated by the fact that these types of controls have often been left in place after the dissipation of the shock that lead to the controls being implemented, the paper evaluates the welfare cost of procrastination in removing these types of controls.     

Shopping from a List: International Studies of Consumer Online Experiences

In response to the growth of online shopping, consumer groups from around the world participated in two mystery shopping exercises. These exercises, conducted during the Christmas holiday seasons of 1998 and 2000, involved buying a variety of products from web sites located both domestically and abroad. A number of serious problems were identified within the research, especially lack of disclosure of key consumer information and failures in delivering goods and refunding consumers when goods were returned. The research has been used by consumer organizations to enhance consumer education and to lobby governmental and self-regulatory bodies for greater consumer protection in the online environment.