Income and the Use of Prescription Drugs by the Elderly: Evidence from the Notch Cohorts

We use exogenous variation in Social Security payments created by the Social Security benefits notch to estimate how retirees' use of prescription medications responds to changes in their incomes. In contrast to estimates obtained using ordinary least squares, instrumental variables estimates based on the notch suggest that lower-income retirees exhibit considerable income sensitivity in their use of prescription drugs. Our estimates are potentially useful for thinking about the health care usage implications of any changes in transfer payments to the elderly that may occur in the future, and for evaluating the benefits of the recently enacted Medicare prescription drug benefit.

Counting seals: estimating the unseen fraction using a covariate and capture-recapture model

Thesis (M.S.) University of Alaska Fairbanks, 2003We evaluated the influences of environmental covariates on the proportion of harbor seals (Phoca vitulina richardsi) ashore on Tugidak Island using a series of photographic capture-recapture experiments and ground based counts. We used general linear models to examine the significance of combinations of covariates including quadratics terms. Time of day, tide height, rate of tide change, surf, and wind speed significantly influenced the number of seals ashore during the molting period. The model including all significant covariates best explained the probability of seals being hauled out. We observed a decline in the local population using the haulout suggesting that seasonal migration affects the number of seals ashore. The relationship between covariates and the number of seals hauled out on Tugidak Island differ in some respects from those reported at other sites in Alaska, implying that a region wide application of a single correction factor to counts of hauled out harbor seals may not adequately account for seals at sea

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

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

Income and the Use of Prescription Drugs by the Elderly: Evidence from the Notch Cohorts

We use exogenous variation in Social Security payments created by the Social Security benefits notch to estimate how retirees\u27 use of prescription medications responds to changes in their incomes. In contrast to estimates obtained using ordinary least squares, instrumental variables estimates based on the notch suggest that lower-income retirees exhibit considerable income sensitivity in their use of prescription drugs. Our estimates are potentially useful for thinking about the health implications of changes in transfer payments to the elderly and for evaluating the benefits of the recently enacted Medicare prescription drug benefit

The Impact of Income on the Weight of Elderly Americans

This paper tests whether income affects the body weight and clinical weight classification of elderly Americans using a natural experiment that led otherwise identical retirees to receive significantly different Social Security payments based on their year of birth. We exploit this natural experiment by estimating models of instrumental variables using data from the National Health Interview Surveys. The model estimates rule out even moderate effects of income on weight and on the probability of being underweight or obese, especially for men.

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