Mean-Variance Preferences and Investor Behaviour

We study the comparative statics implications of mean-variance preferences for optimal portfolios. Specifically, we show that all risk-averse mean-variance investors raise their investment in a risky asset in response to a change in that asset's return distribution if and only if the change lowers both the mean and standard deviation of the return by the same percentage. Besides being of interest in its own right, our results allow us to compare some comparative statics implications and the expected utility and mean-variance models systematically.     

You can't have a CGE recession without excess capacity

Simulations with dynamic, single country, CGE models typically imply that reductions in domestic demand, e.g. a cut in investment, generate increases in exports and reductions in imports facilitated by real depreciation. However, currently in the U.S. a large reduction in investment is occurring simultaneously with a contraction in exports and little movement in the real exchange rate. We show that to describe this situation it is necessary to drop the standard CGE assumption that capital is always fully employed in every industry. After introducing an excess capacity specification, we simulate the U.S. recession with and without the Obama stimulus package.     

Bank reserves: A dispute over words and classification

A prominent philosophical/legal case for requiring 100% bank reserves employs a flawed style of argument. It involves essentialism (criticized by Karl Popper and Joseph Schumpeter), persuasive definitions (identified by Charles L. Stevenson), faulty classification, and the piling up of irrelevant facts and considerations.     

Hedonic price and depreciation indexes for residential housing: A comment

A regression technique for developing residential real estate price indexes using repeat sales on properties has not allowed the separation of depreciation from true price changes. In a recent article Chinloy [2] has proposed a method for achieving this separation. This note shows that his theoretical derivation is incorrect. A corrected model is then used to show the stringent assumptions that are necessary to interpret his empirical results as measuring embodied technological change. The true price effects and the depreciation effects still cannot be separated in such a model.     

A child health production function estimated from longitudinal data. Cebu Study Team

Collaborating researchers used a multi equation model to analyze 3080 mother-infant pairs living on the island of Cebu in the central Philippines and to estimate a child health production function. The econometric methods used eliminated obstacles such as heterogeneity and endogeneity of significant explanatory factors. They also maximized the longitudinal quality of the data. The results showed that morbidity in 1 period reduced infant weight in following periods. For example, diarrhea and febrile respiratory infection reduced growth in the time period following the illnesses. Further effects of some contributing factors were great near birth not diminished with age. For example, breast feeding promoted growth and protected against infection, especially diarrhea and febrile respiratory infection, more substantially near birth than it did later. Further, in urban areas, preventive health care positively affected growth independently of its indirect influence on reducing respiratory infection. Yet it had little effect on diarrhea. Diarrhea had a strong adverse effect on growth. Exposure of the infant to enteric pathogens had the greatest influence on production of diarrhea. In urban areas, exposure included water supply contamination, exposure to feces, a more pathogenic diet, and community crowding. In rural areas, however, exposure included community crowding and increased rainfall which presumably washed feces into the water supply. Household crowding in both urban and rural areas and irritation from smoke in urban areas only tended to bring about febrile respiratory infection.     

Justifying social discounting: The rank-discounted utilitarian approach

The discounted utilitarian criterion for infinite horizon social choice has been criticized for treating generations unequally. We propose an extended rank-discounted utilitarian (ERDU) criterion instead. The criterion amounts to discounted utilitarianism on non-decreasing streams, but it treats all generations impartially: discounting becomes the mere expression of intergenerational inequality aversion. We show that more inequality averse ERDU societies have higher social discount rates when future generations are better off. We apply the ERDU approach in two benchmark economic growth models and prove that it promotes sustainable policies that maximize discounted utilitarian welfare.