A recent article by Phil Davis suggested that the Eigenvalue metric does adds little useful information to the more simply calculated measure of total citations published by the ISI. This paper argues that Davis's claim is an instance of a classic statistical fallacy of spurious correlation. Based on an analysis of the entire 2006 ISI Journal Citation Reports, we show that there are statistically and economically significant differences between the Eigenfactor metrics and the ISI's impact factor and total citations.

The article focuses on the economics of family partnerships. It states an allegory involving a prehistoric couple who split their responsibilities of gathering food and building a fire to create econometric models for family behavior. In theory, monogamous couples have exactly the same interest in their reproductive success, hence completely shared interest in their children. This is not the case in practice, as a variety of marital problems, divorce, and remarriage adversely affect the equation. The observed fact that an increase in a society's wealth tends to decrease family size runs counter to evolutionary biologic theory. No one theory in economics or biology has an adequate explanation for the reduction in family size as wealth increases. A variety of outside factors, notably the decline in child mortality and the change from an agricultural to an urban society, affect the models in both disciplines.

This paper presents a general equilibrium model with marketable pollution permits. It shows that competitive equilibrium with marketable permits is "conditionally optimal" in the sense that no Pareto improvement can be achieved without changing pollution standards. The paper also explores mechanisms for choosing efficient aggregate pollution levels.

This paper describes techniques that I use to teach economics principles "interactively". These techniques include classroom experiments and classroom clickers. The paper describes an experiment on market entry and gives examples of applications of classroom clickers. Clicker applications include the collection data about student preferences that can be used to construct demand curves and supply curves. Check on students' knowledge of central concepts. Play interactive games that illustrate economic concepts.

To answer the question of the paper's title, we looked at the tables of contents from two recent issues of 33 economics journals and attempted to find a freely available online version of each article. We found that about 90 percent of articles in the most-cited economics journals and about 50 percent of articles in less-cited journals are available. We conduct a similar exercise for political science and find that only about 30 percent of the articles are freely available. The paper reports a regression analysis of the effects of author and article characteristics on likelihood of posing and it discusses the implications of self-archiving for the pricing of subscription-based academic journals.

The net present value of costs and benefits from a pay-as-you-go social security system are negative for young people and positive for the elderly. If people all vote their financial self-interest, there will be a pivotal age such that those who are younger favor smaller social security benefits and those who are older will favor larger benefits. For persons of each age and sex, we estimate the expected present value gained or lost from a small permanent increase in the amount of benefits, where the cost of these benefits is divided equally among the population of working age. Assuming that everyone votes his or her long run financial self-interest, and calculating the number of voters in the population of each age and sex, we can determine whether there is majority support for an increase or a decrease in social security benefits. We use statistics on the age distribution and mortality rates for the United States to explore the sensitivity of political support for social security to alternative assumptions about the discount rate, excess burden in taxation, voter participation rates, and birth, death, and migration rates. We find that a once-and-for-all decrease in benefits would be defeated by a majority of selfish voters under a wide range of parameters. We also study the predicted majority outcomes of votes on changing the retirement age.

Students in a large principles class participated in a market experiment in which they had opportunities to take entrepreneurial action. These students had also taken the Meyers-Briggs personality test. We explore the relation between personality characteristics and participation decisions.

The plight of multiracial leukemia patients who are unable to find matching stem cell donors has received much media attention. These news stories, while dramatic, are short on statistical information and long on misconceptions. We apply simple probability theory, the genetics of sexual diploid reproduction, and the theory of public goods to produce estimates of the probabilities that multiracial patients will find matching donors in the existing registry. We then compute the benefits and costs of registering more potential donors of single and mixed races. c

This paper studies a general class of pure exchange economies that have multiple equilibria, which extend an example presented by Lloyd Shapley and Martin Shubik. For such economies, we find easily verified conditions that determine whether there are multiple equilibria. We also provide simple methods for constructing economies in which arbitrary pre-specified sets of prices are equilibria. These economies have simple comparative statics, since prices at interior competitive equilibrium depend on the parameters of utility but not on the endowment quantities.

We provide simple formulas that can be used to calculate ideal bootstrap or exact recombination estimates of group statistics from experimental data.