Lara D. Shore-Sheppard

The Measurement of Medicaid Coverage in the SIPP: Evidence From a Comparison of Matched Records

This article studies the accuracy of reported Medicaid coverage in the Survey of Income and Program Participation (SIPP) using administrative records from the State of California. Overall, we estimate that the SIPP underestimates Medicaid coverage in the California population by about 10%. The probability of correctly reporting coverage for those actually covered by Medicaid is around 85%, and is even higher for low-income children. The probability that people who are not covered by Medicaid incorrectly report that they are covered is about 1.3% for the population as a whole, but is higher (up to 7%) for low-income children.

The Effect of Expanding Medicaid Eligibility on the Distribution of Children's Health Insurance Coverage

Federal legislation passed in the late 1980s greatly expanded the Medicaid program to include children in families with incomes at and above the poverty threshold, regardless of family structure. Using March Current Population Survey data, the author evaluates how the expansions affected private and public insurance coverage levels across the income distribution. Estimates of the extent of take-up of public coverage and substitution of private coverage are used to generate distributions of coverage under two counterfactual situations: absence of expansions, and absence of substitution. The results indicate that the expansions had an equalizing effect on coverage levels across the lower five deciles of the income distribution between 1988 and 1995. In their absence, coverage would have fallen significantly in the third through fifth income deciles. Also, if all of the increased Medicaid enrollment had come from the uninsured population, inequality in coverage levels would have decreased even further.

The Effect of Medicaid Payment Rates on Access to Dental Care among Children

We examine the effect of payment rates on access to dental care among children on Medicaid and on dentists’ participation in Medicaid. Using data from the Survey of Income and Program Participation combined with data on dental fees from 2001 to 2010 and conditioning on state fixed effects, we find a modest positive relationship between Medicaid payment rates and dental care utilization. We test whether higher fees increase the number of dentists accepting Medicaid patients using data from annual surveys of dentists conducted by the American Dental Association between 1999 and 2009. We find a positive, though small, effect of Medicaid payment rates on whether a dentist treats any publicly insured patients and the percentage of the practice’s patients who have public insurance. The estimates imply that increasing Medicaid payments to the level of private market fees would increase access to care, but at a high cost of inducing additional visits.

Industrial Change and Wage Inequality: Evidence from the Steel Industry

The empirical analysis in this paper, which draws on Current Population Survey data, indicates that structural decline in the steel industry during the 1980s markedly affected the distribution of wages both in the industry and in steel-producing communities. The steelworker wage distribution experienced both a drop in the mean and an increase in the variance, becoming very similar to the distribution of wages in other durable goods manufacturing industries. Declines in steel employment substantially increased wage inequality in steel-producing communities, even among workers not employed in steel.

Local Fiscal Policies and Urban Wage Structures

It has long been recognized that average wages vary strikingly across regions and urban areas in part due to differences in local amenities and fiscal policies. However, analogous differences in wage dispersion remain relatively unexplored. The authors develop a model suggesting that, after accounting for individual characteristics, wage dispersion across income groups should reflect differences in the relative valuation of local amenities and fiscal policies. The authors empirically investigate whether there is a link between local taxes and expenditures and the degree of dispersion in the wage structure and find evidence that such a relationship exists.

Stability of children’s insurance coverage and implications for access to care: evidence from the Survey of Income and Program Participation

Even as the number of children with health insurance has increased, coverage transitions—movement into and out of coverage and between public and private insurance—have become more common. Using data from 1996 to 2005, we examine whether insurance instability has implications for access to primary care. Because unobserved factors related to parental behavior and child health may affect both the stability of coverage and utilization, we estimate the relationship between insurance and the probability that a child has at least one physician visit per year using a model that includes child fixed effects to account for unobserved heterogeneity. Although we find that unobserved heterogeneity is an important factor influencing cross-sectional correlations, conditioning on child fixed effects we find a statistically and economically significant relationship between insurance coverage stability and access to care. Children who have part-year public or private insurance are more likely to have at least one doctor’s visit than children who are uninsured for a full year, but less likely than children with full-year coverage. We find comparable effects for public and private insurance. Although cross-sectional analyses suggest that transitions directly between public and private insurance are associated with lower rates of utilization, the evidence of such an effect is much weaker when we condition on child fixed effects.

Expanding Public Health Insurance for Children

The most significant source of health insurance for low-income children is Medicaid, a program jointly funded by the federal and state governments and administered by the states. Over the past fifteen years, Medicaid has undergone substantial changes, most aimed at increasing the availability of public health insurance for children. Prior to the mid-1980s, Medicaid had extremely restrictive eligibility criteria and was tightly linked to the receipt of cash assistance. Consequently, many low-income children were ineligible and uninsured. Uninsured individuals are much less likely to obtain health care and often obtain what care they do receive in relatively costly emergency room settings.1 According to data from the National Medical Expenditure Survey, in 1987 more than half of all uninsured children with asthma and one-third of uninsured children with chronic ear infections did not see a physician (Monheit and Cunningham, 1992). Since the mid-1980s, however, there has been a major expansion of coverage to children previously ineligible, a break in the link between cash assistance and health insurance, the introduction of a new program (the State Children’s Health Insurance Program), and a move to place greater authority for public health insurance programs in the hands of the states. These changes, the most far-reaching since Medicaid’s inception in 1965, affect the lives of a substantial number of American children—according to Census Bureau data, 14.5 million children (approximately 20 percent of all children) report being covered by Medicaid in 1999 (the number of children receiving Medicaid according to administrative data is higher—18.3 million in 1998), and research shows that an even larger number of children were eligible for public insurance.

The Employment Dynamics of Disadvantaged Women: Evidence from the SIPP

Understanding the employment dynamics of disadvantaged families is increasingly important. We estimate duration models describing these dynamics for disadvantaged single mothers and use them to conduct a rich set of counterfactual analyses. We use a misreporting model to correct for “seam bias,” the problem that too many transitions are reported between reference periods in panel data. We find effects of demographics, minimum wages, unemployment rates, and maximum welfare benefits, but not policy changes introduced through state welfare waivers, on employment dynamics. We find that two commonly used ad hoc methods of addressing seam bias perform substantially worse than our approach.

Estimating Heterogeneous Takeup and Crowd-Out Responses to Existing Medicaid Income Limits and their Nonmarginal Expansions

We use a switching probit model and the income-limit-based structure of Medicaid eligibility for children to estimate treatment effects of nonmarginal Medicaid expansions on Medicaid takeup, private insurance coverage, and crowd-out, as well as crowd-out for those eligible for Medicaid under rules already in place. Many of these estimates are not found in existing work on public insurance and cannot be calculated with the linear probability model used by previous work in this literature. We provide an estimation approach that is straightforward to implement yet yields precise treatment effects.

Income dynamics and the Affordable Care Act.

OBJECTIVE To examine the sources of family income dynamics leading to movement into and out of Medicaid expansion and subsidy eligibility under the Affordable Care Act. DATA SOURCE Survey of Income and Program Participation (SIPP): 1996, 2001, 2004, 2008 panels. STUDY DESIGN Considering four broad subsidy eligibility categories for monthly Modified Adjusted Gross Income (MAGI) (<138 percent of the Federal Poverty Level [FPL], 138-250 percent FPL, 250-400 percent FPL, and >400 percent FPL), I use duration analysis to examine determinants of movements between categories over the course of a year. DATA COLLECTION/EXTRACTION Using detailed monthly data, I determine the members of tax-filing units and calculate an approximation of MAGI at the monthly level. The analysis sample is adults ages 22-64 years. PRINCIPAL FINDINGS Incomes are highly variable within a year, particularly at the lower end of the income distribution. Employment transitions, including transitions not involving a period of nonemployment, and family structure changes strongly predict sufficient income volatility to trigger a change in subsidy category. CONCLUSIONS Income volatility arising from employment and family structure changes is likely to trigger changes in subsidy eligibility within the year, but the sources and effects of the volatility differ substantially depending on the individuals position in the income distribution.