Can Policy Changes Be Treated as Natural Experiments? Evidence from State Excise Taxes

An important issue in public policy analysis is the potential endogeneity of the policies under study. If policy changes constitute responses on the part of political decision-makers to changes in a variable of interest, then standard analyses that treat policy changes as natural experiments may yield biased estimates of the impact of the policy (Besley and Case 2000). We examine the extent to which such political endogeneity biases conventional fixed effects estimates of behavioral parameters by identifying the elasticities of demand for cigarettes and beer using the timing of state legislative elections as an instrument for changes in state excise taxes. In both cases, we find sizable differences between these estimated demand elasticities and the fixed effect estimates cited in Evans, Ringel, and Stech (1999). We conclude that the use of fixed effects estimators in environments where policy interventions are endogenously determined may lead to large biases in the estimated effects of the policies. This paper was revised July 2002

Can Policy Changes Be Treated as Natural Experiments? Evidence from Cigarette Excise Taxes

An important issue in public policy analysis is the potential endogeneity of the policies under study. We examine the extent to which such political endogeneity biases estimates of behavioral parameters by identifying the elasticity of demand for cigarettes using the timing of state legislative elections as an instrument for changes in cigarette excise taxes. We find sizable differences between our estimates and those cited in Chaloupka and Warner (2000), which treat cigarette taxes as exogenous. Our results add to a growing body of evidence that policy changes may be codetermined with the outcomes they are thought to influence

Can Policy Changes Be Treated as Natural Experiments? Evidence from State Excise Taxes

An important issue in public policy analysis is the potential endogeneity of the policies under study. If policy changes constitute responses on the part of political decision-makers to changes in a variable of interest, then standard analyses that treat policy changes as natural experiments may yield biased estimates of the impact of the policy (Besley and Case 2000). We examine the extent to which such political endogeneity biases conventional fixed effects estimates of behavioral parameters by identifying the elasticities of demand for cigarettes and beer using the timing of state legislative elections as an instrument for changes in state excise taxes. In both cases, we find sizable differences between these estimated demand elasticities and the fixed effect estimates cited in Evans, Ringel, and Stech (1999). We conclude that the use of fixed effects estimators in environments where policy interventions are endogenously determined may lead to large biases in the estimated effects of the policies

Lethal Elections: Gubernatorial Politics and the Timing of Executions

We document the existence of a gubernatorial election cycle in state executions, suggesting that election year political considerations play a role in determining the timing of executions. Our analysis indicates that states are approximately 25 percent more likely to conduct executions in gubernatorial election years than in other years. We also find that elections have a larger effect on the probability that an African American defendant will be executed in a given year than on the probability that a white defendant will be executed, and that the overall effect of elections is largest in the South. These findings raise concerns that state executions may fail to meet the constitutional requirements stipulated by the U.S. Supreme Court in *Gregg v. Georgia* for the administration of state death penalty laws. This paper was revised July 2002

Emergence of the Shackleton Range from beneath the Antarctic Ice Sheet due to glacial erosion

This paper explores the long-term evolution of a subglacial fjord landscape in the Shackleton Range, Antarctica. We propose that prolonged ice-sheet erosion across a passive continental margin caused troughs to deepen and lower the surrounding ice-sheet surface, leaving adjacent mountains exposed. Geomorphological evidence suggests a change in the direction of regional ice flow accompanied emergence. Simple calculations suggest that isostatic compensation caused by the deepening of bounding ice-stream troughs lowered the ice-sheet surface relative to the mountains by ~800m. Use of multiple cosmogenic isotopes on bedrock and erratics (26Al, 10Be, 21Ne) provides evidence that overriding of the massif and the deepening of the adjacent troughs occurred earlier than the Quaternary. Perhaps this occurred in the mid-Miocene, as elsewhere in East Antarctica in the McMurdo Dry Valleys and the Lambert basin. The implication is that glacial erosion instigates feedback that can change ice-sheet thickness, extent, and direction of flow. Indeed, as the subglacial troughs evolve over millions of years, they increase topographic relief; and this changes the dynamics of the ice sheet. © 2013 Elsevier B.V

Social Interactions and the Health Insurance Choices of the Elderly: Evidence from the Health and Retirement Study

Using data from the 1998 Wave of the Health and Retirement Study, we examine the effect of social interactions on the health insurance choices of the elderly. We find that having more social interactions, as measured by contacts with friends and neighbors, reduces the likelihood of enrolling in a Medicare managed care plan relative to purchasing a medigap policy or having coverage through Medicare alone. Our estimates indicate that social networks are an important determinant of the health insurance choices of the elderly and provide suggestive evidence that word-of-mouth information sharing may have played a role in the preference of some seniors for traditional indemnity insurance over managed care

LCDG4 and DigiSim - Simulation activities at NICADD/NIU

We present two software packages developed to support detector R&D studies for the International Linear Collider. LCDG4 is a full-detector simulator that provides energy deposits from particles traversing the sensitive volumes of the detector. It has been extensively used within the American ILC community, providing data for algorithm development and detector optimization studies. DigiSim models real-life digitization effects, converting the idealized response into simulated detector readout. It has many useful features to improve the realism in modeling detector response. The main characteristics of these two complementary packages are discussed.Comment: 8 pages, 7 figures, submitted to LCWS05 conference proceedings. Uses slac_one.rt

Social Interaction and the Health Insurance Choices of the Elderly

Using data from the 1998 wave of the Health and Retirement Study, we examine the effect of social interactions on the health insurance choices of the elderly. We find that having more social interactions, as measured by contacts with friends and neighbors, reduces the likelihood of enrolling in a Medicare managed care plan relative to purchasing a medigap policy or having coverage through Medicare alone. Our estimates indicate that social networks are an important determinant of the health insurance choices of the elderly and provide suggestive evidence that word-of-mouth information sharing may have played a role in the preference of some seniors for traditional indemnity insurance over managed care