The recent article in this Review by Anthony Fisher, John Krutilla, and Charles Cicchetti (F-K-C) is an important step towards the development of a general method of analysis of the economics of environmental preservation. They are also commended for their attempt to adapt their model to the investigation of an important environmental policy question concerning the advisability of hydroelectric development in the Hells Canyon region of the Snake River. We feel, however, there is room for improvement in their theoretical models and perhaps in the presentation of empirical results. Sections I and II of their article consist of the development of an allocation model of some degree of sophistication from which some general conclusions are drawn which are not necessarily true. For instance, in Section I, it is stated that .... the marginal opportunity costs of development, the benefits from preservation, are increasing as development increases (p. 607). This certainly follows from the assumptions upon which their model is based; i.e., from their assumptions it follows BPD>0. It is not completely relevant, however, for as their later analysis indicates, the important question is what happens to total benefits rather than marginal. With respect to the portion of Hells Canyon in question, the present level of developed area is very small. Since almost all of the area is in a preserved state, i.e., P_L their assumptions BD> 0 and BDD <0 imply the marginal benefits of development are relatively large. Thus in seeking an optimal allocation of the land between preservation and development, we would seek to increase marginal benefits from preservation and decrease marginal benefits from development. Thus we would seek to increase the developed area D. We might also point out an undeveloped Hells Canyon may be so unique a natural resource that, as F-K-C suggest, there are no adequate substitutes of like quality and as such their procedures are justified. In general, however, we should note theirs is basically a suboptimization procedure in it isolates its analysis upon a single area without regard to other areas. Thus, if such a method were to be used in a piecemeal area by area decision process, the end result may be far from optimnal for the total environment. In Section II, F-K-C use the concept of total benefits and conclude . . as benefits from preservation increase relative to benefits from development, the optimal short-run level of development D*(t) decreases (p. 611). The justification for this statement is provided in their footnote 17. There they correctly derive the relation

A MACROECONOMIC AND TRANSPORT MODEL HAS BEEN DEVELOPED TO EXPLORE THE INTERFACE BETWEEN THE ECONOMY OF AN UNDERDEVELOPED NATION AND ITS TRANSPORTATION SYSTEM. THE MACROECONOMIC PORTION OF THE MODEL PRODUCES ANNUAL PROJECTIONS OF REGIONAL DEMANDS, PRODUCTION LEVELS, AND INCOMES. THE TRANSPORT SECTOR DETERMINES MARKET AREAS, DISTRIBUTION AND ROUTING OF THESE COMMODITY FLOWS, AND ASSIGNS THEM TO THE LINKS OF A NETWORK REPRESENTING THE INDIVIDUAL TRANSPORT FACILITIES EXISTING OR PROPOSED FOR THE COUNTRY OR REGION UNDER STUDY. THE COUNTRY OF COLOMBIA, SOUTH AMERICA WAS CHOSEN FOR EXPERIMENTATION WITH THE MODEL. IT IS CONCLUDED THAT THE MODEL IS USEFUL FROM BOTH A PRACTICAL AND A PEDAGOGICAL STANDPOINT. IN THE DISCUSSION, IT IS NOTED THAT THE CRUX OF THE MATTER MAY WELL BE IN THE DYNAMIC INTERACTION BETWEEN THE TRANSPORTATION SECTOR AND THE REST OF THE ECONOMY. A PRINCIPAL FEATURE OF THIS MODEL IS JUST THIS DYNAMIC INTERACTION. IT IS CONCLUDED THAT THE ABOVE MODEL CANNOT HELP WITH SOME IMPORTANT CLASSES OF TRANSPORT QUESTIONS, BUT THAT THERE ARE A LARGE NUMBER OF TRANSPORT PROBLEMS IN LESS DEVELOPED ECONOMIES FOR WHICH IT IS WELL SUITED. /BPR/

In recent years, the concern about the tradeoffs between economic growth and environmental quality have been paramount. To a large extent, the energy sector has been the locus of the major battles. For the most part, the concerns have been with local environmental problems such as disputes over air and water quality, nuclear accidents, and radioactive wastes. Although these problems have not been solved, it appears that as a result of considerable technical work that techniques exist (even if political will does not) to reduce most local environmental problems to a tolerable level. There remain on the agenda, however, a number of global environmental problems, and again these relate mainly to the energy sector. In particular, it appears that emissions of carbon dioxide particulate matter, and waste heat may, at some time in the future, lead to significant climatic modifications. Of these, it appears that carbon dioxide will probably be the first man-made emission to affect climate on a global scale, with a significant temperature increase by the end of the century.

This paper asks whether elite colleges help students outside of historically advantaged groups reach top positions in the economy. I combine administrative data on income and leadership teams at publicly traded firms with a regression discontinuity design based on admissions rules at elite business-focused degree programs in Chile. The 1.8 percent of college students admitted to these programs account for 41 percent of leadership positions and 39 percent of top 0.1 percent incomes. Admission raises the number of leadership positions students hold by 44 percent and their probability of attaining a top 0.1 percent income by 51 percent. However, these gains are driven by male applicants from high-tuition private high schools, with zero effects for female students or students from other school types with similar admissions test scores. Admissions effects are equal to 38 percent of the gap in rates of top attainment by gender and 54 percent of the gap by high school background for male students. A difference-in-differences analysis of the rates at which pairs of students lead the same firms suggests that peer ties formed between college classmates from similar backgrounds may play an important role in driving the observed effects.

Charter school funding is typically set by formulas that provide the same amount for students regardless of advantage or need. I present evidence that this policy skews the distribution of students served by charters toward low-cost populations by influencing where charter schools open and whether they survive. To do this, I develop and estimate an equilibrium model of charter school supply and competition to evaluate the effects of funding policies that aim to correct these incentives. The results indicate that a cost-adjusted funding formula would increase the share of disadvantaged students in charter schools with little reduction in aggregate effectiveness.