The Deterrent Effect of Death Penalty Eligibility: Evidence from the Adoption of Child Murder Eligibility Factors

We draw on within-state variations in the reach of capital punishment statutes between 1977 and 2004 to identify the deterrent effects associated with capital eligibility. Focusing on the most prevalent eligibility expansion, we estimate that the adoption of a child murder factor is associated with an approximately 20% reduction in the homicide rate of youth victims. Eligibility expansions may enhance deterrence by (1) paving the way for more executions and (2) providing prosecutors with greater leverage to secure enhanced non-capital sentences. While executions themselves are rare, this latter channel is likely to be triggered fairly regularly, providing a reasonable basis for a general deterrent response

Using a Laplace approximation to estimate the random coefficients logit model by non-linear least squares

Current methods of estimating the random coefficients logit model employ simulations of the distribution of the taste parameters through pseudo-random sequences. These methods suffer from difficulties in estimating correlations between parameters and computational limitations such as the curse of dimensionality. This paper provides a solution to these problems by approximating the integral expression of the expected choice probability using a multivariate extension of the Laplace approximation. Simulation results reveal that our method performs very well, both in terms of accuracy and computational time. This paper is a revised version of CWP01/06.

The Deterrent Effect of Expansions in Death Penalty Eligibility Criteria

Homicides must possess certain characteristics before they become eligible for capital punishment. Over the last several decades, virtually every state has added to its list of possible eligibility criteria. We draw on this variation to identify deterrent effects of the eligibility expansions. Eligibility expansions may deter future homicides through two channels: (1) by paving the way for more death sentences and executions and (2) by providing prosecutors with greater leverage to secure enhanced sentences (capital or non-capital). The latter channel is likely to be triggered on a fairly common basis. We estimate that the adoption of a law making child murders specifically eligible for capital punishment is associated with an approximately 19% reduction in the rate of homicides of youth victims. We estimate deterrence findings of similar magnitude when we turn to the estimation of an empirical specification that draws on variations in the full set of eligibility criteria and that parameterizes general eligibility statutes using a simulated measure of the propensity of each state to extend capital eligibility to a given murder. However, the findings of this general deterrence investigation are relatively noisy and are not robust to the exclusion of the child-murder factor from the simulation analysis.Capital Punishment Deterrent, Captial Punishment Eligibility Expansion

A Photon Splitting Cascade Model of Soft Gamma-Ray Repeaters

The spectra of soft gamma-ray repeaters (SGRs), with the exception of the March 5, 1979 main burst, are characterized by high-energy cutoffs around 30 keV and low-energy turnovers that are much steeper than a Wien spectrum. Baring (1995) found that the spectra of cascades due to photon splitting in a very strong, homogeneous magnetic field can soften spectra and produce good fits to the soft spectra of SGRs. Magnetic field strengths somewhat above the QED critical field strength $B_{\rm cr}$, where $B_{\rm cr} = 4.413 \times 10^{13}$ G, is required to produce cutoffs at 30-40 keV. We have improved upon this model by computing Monte Carlo photon splitting cascade spectra in a neutron star dipole magnetic field, including effects of curved space-time in a Schwarzschild metric. We investigate spectra produced by photons emitted at different locations and observer angles. We find that the general results of Baring hold for surface emission throughout most of the magnetosphere, but that emission in equatorial regions can best reproduce the constancy of SGR spectra observed from different bursts.Comment: 5 pages in LATEX using REVTEX aipbook.sty + 4 figures (uuencoded, compressed postscript), to appear in the proceedings of the Third Huntsville Workshop on Gamma-Ray Bursts, eds. C. Kouveliotou, M. S. Briggs and G. J. Fishman (New York, AIP

A New Class of Radio Quiet Pulsars

The complete absence of radio pulsars with periods exceeding a few seconds has lead to the popular notion of the existence of a high $P$ death line. In the standard picture, beyond this boundary, pulsars with low spin rates cannot accelerate particles above the stellar surface to high enough energies to initiated pair cascades through curvature radiation, and the pair creation needed for radio emission is strongly suppressed. In this paper we postulate the existence of another pulsar ``death line,'' corresponding to high magnetic fields $B$ in the upper portion of the $\dot{P}$--$P$ diagram, a domain where few radio pulsars are observed. The origin of this high $B$ boundary, which occurs when $B$ becomes comparable to or exceeds $10^{13}$ Gauss, is again due to the suppression of magnetic pair creation $\gamma\to e^+e^-$, but in this instance, primarily because of ineffective competition with the exotic QED process of magnetic photon splitting. This paper describes the origin, shape and position of the new ``death line,'' above which pulsars are expected to be radio quiet, but perhaps still X-ray and $\gamma$-ray bright.Comment: 5 pages, including 1 eps figure, to appear in Proc. 4th Compton Symposium, (1997) ed. Dermer, C. D. & Kurfess, J. D. (AIP, New York

The Effect of Statutory Rape Laws on Teen Birth Rates

Policymakers have often been explicit in expanding statutory rape laws to reduce teenage pregnancies and live births by teenage mothers, often with the goal of reducing associated welfare outlays. In this paper, we explore whether expansions in such laws are indeed associated with reductions in teen birth rates. In order to codify statutory-rape-law expansions, we use a national micro-level sample of sexual encounters to simulate the degree to which such encounters generally implicate the relevant laws. By codifying statutory-rape laws in terms of their potential reach into sexual encounters, as opposed to using crude binary treatment variables, this simulation approach facilitates the use of multi-state difference-in-difference designs in the face of highly heterogeneous legal structures. Our results suggest that live birth rates for teenage mothers fall by roughly 4.5 percent (or 0.1 percentage points) upon a 1 standard-deviation increase in the share of sexual activity among a given age group that triggers a felony for the elder party to the encounter. This response, however, is highly heterogeneous across ages and weakens notably in the case of the older teen years. Furthermore, we do not find strong results suggesting a further decline in birth rates upon increases in punishment severities

Using a Laplace approximation to estimate the random coefficients logit model by non-linear least squares

Current methods of estimating the random coefficients logit model employ simulations of the distribution of the taste parameters through pseudo-random sequences. These methods suffer from difficulties in estimating correlations between parameters and computational limitations such as the curse of dimensionality. This paper provides a solution to these problems by approximating the integral expression of the expected choice probability using a multivariate extension of the Laplace approximation. Simulation results reveal that our method performs very well, both in terms of accuracy and computational time.

Finding the Limits of Aid/Watch

Commissioner of Taxation v Aid/Watch Incorporated is the latest of a series of recent cases in which the High Court of Australia has exhibited what might be described as a ‘generosity of spirit’ to would-be taxpayers whose charitable status has been called into question. In Aid/Watch, the Court ruled that an organisation formed to monitor and evaluate the delivery of foreign aid by Australian government agencies was a charity even though it was engaged, consistently with its objects, in the sorts of political activities that traditionally have been regarded as anathema to charity. This article considers where we might feasibly locate the boundaries of the High Court’s reasoning in Aid/Watch, in light of charity law as a whole. In other words, as a matter of charity law, what are the limits of Aid/Watch? Thinking about this question demands: (a) some understanding of what the High Court in Aid/Watch said with certainty; and (b) a wider review of charity law to see which of its rules and principles may bear upon cases about political purposes now that Aid/Watch has been decided