The Digrams of Webster\u27s Unabridged Dictionary

For many years word buffs at these laboratories have made a game out of finding words which contain strange digrams (pairs of letters side-by-side). The problem, as originally posed by M.D. McIlroy, was to complete a table with 26 rows and 26 columns, labeled by the letters A, B, ... , Z. The space where row L crossed column L\u27 was to be filled by a word containing the digram LL\u27

The Twenty-Fifth Amendment and the Establishment of Medical Impairment Panels: Are the Two Safely Compatible?

At least two proposals have been offered by prominent members of the medical community to establish “Medical Impairment Panels” to monitor the health of Presidents of the United States and to facilitate the implementation of relevant Sections of the Twenty-Fifth Amendment. The first discussed in this Article was made by Dr. Herbert Abrams, a now deceased professor of radiology at Stanford University; the second by Dr. Bert Park, a prominent Missouri neurosurgeon. Dr. Abrams and Dr. Park spoke and wrote about their plans frequently over the years. The objective of each proposal was to ensure that the Vice President, the Cabinet, and Congress are informed as to situations when a President might be seriously impaired in terms of carrying out his or her official responsibilities as President of the United States. This Article assesses each proposal in turn

Specification Testing in Panel Data With Instrumental Variables

This paper shows a convenient way to test whether instrumental variables are correlated with individual effects in a panel data set. It shows that the correlated fixed effects specification tests developed by Hausman and Taylor (1981) extend in an analogous way to panel data sets with endogenous right hand side variables. In the panel data context, different sets of instrumental variables can be used to construct the test. Asymptotically, I show that the test in many cases is more efficient if an incomplete set of instruments is used. However, in small samples one is likely to do better using the complete set of instruments. Monte Carlo results demonstrate the likely gains for different assumptions about the degree of variance in the data across observations relative to variation across time.

Investment in Energy Infrastructure and the Tax Code

Federal tax policy provides a broad array of incentives for energy investment. I review those policies and construct estimates of marginal effective tax rates for different energy capital investments as of 2007. Effective tax rates vary widely across investment classes. I then consider investment in wind generation capital and regress investment against a user cost of capital measure along with other controls. I find that wind investment is strongly responsive to changes in tax policy. Based on the coefficient estimates the elasticity of investment with respect to the user cost of capital is in the range of -1 to -2. I also demonstrate that the federal production tax credit plays a key role in driving wind investment over the past eighteen years.electricity, wind power, production tax credits, tax subsidies

Environmental Levies and Distortionary Taxation: Pigou, Taxation, and Pollution

Bovenberg and de Mooij (1994) showed that, in the presence of preexisting distorting taxes, the optimal pollution tax typically lies below social marginal damages. Many have viewed this result as a refutation of the so-called double dividend hypothesis,' which suggests that a tax on pollution can both improve the environment and reduce distortions in the tax system. Bovenberg and de Mooij's paper triggered a large literature on optimal environmental tax rates in a second-best world. In this note, I argue that the emphasis on tax rates is misguided. Using an analytical general equilibrium model, I show that for reasonable parameter values, an increase in tax distortions (arising from an increase in required tax revenues) leads to a fall in the optimal Pigouvian tax rate even while environmental quality improves. In general, knowledge of the direction of changes in optimal environmental tax rates due to changes in the economy is not sufficient for understanding the impact on environmental quality.