Showing papers in "Journal of Policy Analysis and Management in 2005"
TL;DR: This paper showed that accountability systems introduced during the 1990s had a clear positive impact on student achievement, but did not lead to any narrowing in the Black-White achievement gap (though it did narrow the Hispanic-white achievement gap).
Abstract: The leading school reform policy in the United States revolves around strong accountability of schools with consequences for performance. The federal government's involvement through the No Child Left Behind Act of 2001 reinforces the prior movement of many states toward policies based on measured student achievement. Analysis of state achievement growth as measured by the National Assessment of Educational progress shows that accountability systems introduced during the 1990s had a clear positive impact on student achievement. This single policy instrument did not, however, also lead to any narrowing in the Black-White achievement gap (though it did narrow the Hispanic-White achievement gap). Moreover, the Black-White gap appears to have been adversely impacted over the decade by increasing minority concentrations in the schools. An additional issue surrounding stronger accountability has been a concern about unintended outcomes related to such things as higher exclusion rates from testing, increased dropout rates, and the like. Our analysis of special education placement rates, a frequently identified area of concern, does not show any responsiveness to the introduction of accountability systems.© 2005 by the Association for Public Policy Analysis and Management
517 citations
TL;DR: In this article, the authors investigated whether ISO 14001, a voluntary program with a weak sword, can mitigate shirking and improve participants' environmental performance, and they found that ISO-14001 certified facilities reduce their pollution emissions more than non-certified facilities.
Abstract: Voluntary environmental programs are codes of progressive environmental conduct that firms pledge to adopt. This paper investigates whether ISO 14001, a voluntary program with a weak sword—a weak monitoring and sanctioning mechanism—can mitigate shirking and improve participants’ environmental performance. Sponsored by the International Organization for Standardization (ISO), ISO 14001 is the most widely adopted voluntary environmental program in the world. Our analysis of over 3,000 facilities regulated as major sources under the U.S. Clean Air Act suggests that ISO 14001-certified facilities reduce their pollution emissions more than noncertified facilities. This result persists even after controlling for facilities’ emission and regulatory compliance histories as well as addressing potential endogeneity issues between facilities’ environmental performance and their decisions to join ISO 14001. © 2005 by the Association for Public Policy Analysis and Management
425 citations
TL;DR: This paper found that teachers express preferences to teach close to where they grew up and, controlling for proximity, prefer areas with characteristics similar to their hometown, and discussed implications of these preferences for the successful recruitment of teachers, including the potential benefits of local recruiting and training.
Abstract: This paper explores a little-understood aspect of labor markets, their spatial geography. Using data from New York State, we find teacher labor markets to be geographically very small. Teachers express preferences to teach close to where they grew up and, controlling for proximity, they prefer areas with characteristics similar to their hometown. We discuss implications of these preferences for the successful recruitment of teachers, including the potential benefits of local recruiting and training. We also discuss implications for the modeling of teacher labor markets, including the possible biases that arise in estimates of compensating differentials when distance is omitted from the analyses. This study contributes to the literature on the geography of labor markets more generally by employing data on residential location during childhood instead of current residence, which may be endogenous to job choice. © 2005 by the Association for Public Policy Analysis and Management.
405 citations
TL;DR: This paper conducted a meta-analysis of 49 environmental equity studies and found that while there is ubiquitous evidence of environmental inequities based upon race, existing research does not support the contention that similar inequities exist with respect to economic class.
Abstract: Over the past decade activists, academics, and policymakers have devoted a great deal of attention to “environmental equity,” or the notion that sources of potential environmental risk may be concentrated among racial and ethnic minorities and the poor Despite these efforts, the existence and extent of environmental inequities is still the subject of intense scholarly debate This manuscript reports the results from a meta-analysis of 49 environmental equity studies The analysis demonstrates that while there is ubiquitous evidence of environmental inequities based upon race, existing research does not support the contention that similar inequities exist with respect to economic class © 2005 by the Association for Public Policy Analysis and Management
309 citations
TL;DR: Evaluating the selection problem of WIC using rich data from the national Pregnancy Risk Assessment Monitoring System shows that relative to Medicaid mothers, WIC participants are negatively selected on a wide array of observable dimensions, and yet WIC participation is associated with improved birth outcomes, even after controlling for observables.
Abstract: Support for WIC, the Special Supplemental Nutrition Program for Women, Infants, and Children, is based on the belief that "WIC works." This consensus has lately been questioned by researchers who point out that most WIC research fails to properly control for selection into the program. This paper evaluates the selection problem using rich data from the national Pregnancy Risk Assessment Monitoring System. We show that relative to Medicaid mothers, all of whom are eligible for WIC, WIC participants are negatively selected on a wide array of observable dimensions, and yet WIC participation is associated with improved birth outcomes, even after controlling for observables and for a full set of state-year interactions intended to capture unobservables that vary at the state-year level. The positive impacts of WIC are larger among subsets of even more disadvantaged women, such as those who received public assistance last year, single high school dropouts, and teen mothers.
302 citations
TL;DR: In this paper, the authors explore the continuing decline in employment and labor force participation of non-rolled Black men between the ages of 16 and 34 who have a high school education or less in the 1980s and 1990s.
Abstract: In this paper, we explore the continuing decline in employment and labor force participation of nonenrolled Black men between the ages of 16 and 34 who have a high school education or less in the 1980s and 1990s. We focus on two fairly new developments: (1) the dramatic growth in the number of young Black men who have been incarcerated and (2) strengthened enforcement of child support policies. We analyze micro-level data from the Current Population Survey Outgoing Rotation Groups (CPS-ORG), into which state-level data over time on incarceration rates and child support enforcement have been merged. Our results indicate that previous incarceration and child support enforcement can account for half or more of the decline in employment activity among Black men aged 25–34. Previous incarceration also contributes to the decline among those aged 16–24. © 2005 by the Association for Public Policy Analysis and Management
202 citations
TL;DR: Whether income is linked to overweight in school-age children and whether food programs such as the Food Stamp Program, the National School Lunch Program, and the School Breakfast Program are associated with overweight among children in different income groups is examined.
Abstract: Sixteen percent of children 6-11 years of age were classified as overweight in 1999-2002, four times the percentage in 1965. Although poverty has traditionally been associated with underweight as a result of poor diet, researchers have recently pointed to a paradox in the U.S., which is that low income and obesity can coexist in the same population. This paper first examines whether income is linked to overweight in school-age children. Second, it explores whether food programs such as the Food Stamp Program, the National School Lunch Program, and the School Breakfast Program are associated with overweight among children in different income groups. The data come from the nationally representative 1997 Panel Study of Income Dynamics Child Development Supplement. No evidence either that poor children are more likely to be overweight or that food programs contribute to overweight among poor children was found.
140 citations
TL;DR: It is found that an increase of one pill per capita is associated with a 2.5 percent reduction in suicide rates, a relationship that is more pronounced for adults than for children.
Abstract: Policymakers are increasingly concerned that a relatively new class of anti-depressant drugs, selective serotonin re-uptake inhibitors (SSRI), may increase the risk of suicide for at least some patients, particularly children. Prior randomized trials are not informative on this question because of small sample sizes and other limitations. Using variation across countries over time in SSRI sales and suicide, we find that an increase of one pill per capita (a 13 percent increase over 1999 levels) is associated with a 2.5 percent reduction in suicide rates, a relationship that is more pronounced for adults than for children. Our findings suggest that expanding access to SSRIs for adults may be a cost-effective way to save lives, although policymakers are right to remain cautious about pediatric use of SSRIs.
138 citations
TL;DR: In this article, the authors studied the performance of the state-of-the-art K-12 education systems in the context of the first decade of the emergence of the Internet.
Abstract: Since the inception of charter schools over a decade ago, policymakers have wanted to know how charter schools are performing.
135 citations
TL;DR: It is found that former welfare recipients who are both White and morbidly obese have been less successful in transitioning from welfare to work, consistent with unobserved heterogeneity causing the correlation between morbid obesity and labor market outcomes.
Abstract: This paper utilizes a rich longitudinal data set--the Women's Employment Study (WES)--to investigate whether obesity, which is common among women of low socioeconomic status, is a barrier to employment and earnings for current and former welfare recipients. We find that former welfare recipients who are both White and morbidly obese have been less successful in transitioning from welfare to work. These women are less likely to work at any survey wave, spend a greater percentage of months between waves receiving cash welfare, and have lower monthly earnings at each wave. The magnitude of the difference in labor market outcomes between the morbidly obese and those who are less heavy is in some cases similar in magnitude to the differences in these labor market outcomes between high school dropouts and graduates. In contrast, we find no such labor market differences associated with morbid obesity for African-American respondents. This paper documents the relationship between weight and labor market outcomes for the first time among the welfare population. In addition, it investigates whether the correlation for White females is due to unobserved heterogeneity. We find that after controlling for individual fixed effects, the point estimate of the correlation of morbid obesity and each of the labor market outcomes falls considerably and is no longer statistically significant. These results are consistent with unobserved heterogeneity causing the correlation between morbid obesity and labor market outcomes. Findings are similar after controlling for the respondent's mental and physical health.
89 citations
TL;DR: This paper explores whether the specific design of a state's program has contributed to its success in meeting two objectives of the Children's Health Insurance Program (SCHIP): increasing the health insurance Coverage of children in lower income families and doing so with a minimum reduction in their private health insurance coverage (crowd-out).
Abstract: In this paper, we explore whether the specific design of a state's program has contributed to its success in meeting two objectives of the Children's Health Insurance Program (SCHIP): increasing the health insurance coverage of children in lowerincome families and doing so with a minimum reduction in their private health insurance coverage (crowd-out). In our analysis, we use two years of Current Population Survey data, 2000 and 2001, matched with detailed data on state programs. We focus on two populations: the eligible population of children, broadly defined—those living in families with incomes below 300 percent of the federal poverty line (FPL)—and a narrower group of children, those who we estimate are eligible for Medicaid or SCHIP. Unique state program characteristics in the analysis include whether the state plan covers families; whether the state uses presumptive eligibility; the number of months without private coverage that are required for eligibility; whether there is an asset test; whether a face-to-face interview is required; and specific outreach activities. Our results provide evidence that state program characteristics are significant determinants of program success. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: In this article, the authors used toxic chemical release data, modeled for toxicity and dispersion in square kilometer units across 45 states, to test six sets of hypotheses of potential interactions between facilities and the communities surrounding them.
Abstract: Decreases over time in pounds of industrial chemical emissions have led to concerns that nonminority, higher-income communities have benefited disproportionately in reductions in risk. Toxic chemical release data, modeled for toxicity and dispersion in square kilometer units across 45 states, are used to test six sets of hypotheses of potential interactions between facilities and the communities surrounding them. The results provide mixed evidence that ethnicity explains chemical emission changes. Stronger support is found that changes in emission patterns are affected by a community's ability to process complex information and its capacity for collective action, and industrial production factors. Some support is found for the efficacy of state environmental policies that both do and do not fit the traditional regulatory model in encouraging risk reductions. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: This article found that exogenous increases in work induced by an experimental tax credit led to the predicted change in beliefs among younger workers, while welfare recipients who have a more positive view of work are the ones who are more likely to work.
Abstract: A common argument in support of work-based welfare reform is that exposure to work will lead welfare recipients to revise their beliefs about how they will be treated in the labor market. This paper explores the analytical and empirical basis for this argument. The difficulty in testing the assumption that work leads to a change in beliefs is that there is an inherent simultaneity between work and beliefs. Welfare recipients who work may have different beliefs because they learn about the world of work once they enter the labor market. Alternatively, welfare recipients who have a more positive view of work are the ones who are more likely to work. We use a unique data set that helps solve this simultaneity problem. We find that exogenous increases in work induced by an experimental tax credit led to the predicted change in beliefs among younger workers. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: The authors used data from a sample of applicants to a national means-tested school voucher program and a national sample of the population eligible for the program to evaluate the factors leading families to use school vouchers.
Abstract: We use data from a sample of applicants to a national means-tested school voucher program and a national sample of the population eligible for the program to evaluate the factors leading families to use school vouchers. Our analysis divides the process of voucher usage into two distinct stages: initial application and subsequent take-up. Using a nested logit model, we find that some factors, like religious affiliation and religious service attendance, affect both stages. Others, like mother's education, affect only one (application). Still others, like ethnicity, have opposite effects at the two stages. Compared to Whites, minorities are more likely to apply for vouchers, but less likely to take them when given the opportunity. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: In this paper, the authors analyzed the relationship between prenatal WIC participation and birth outcomes in New York City from 1988-2001, focusing on measures of fetal growth distinct from preterm birth, since there is little clinical support for a link between nutritional supplementation and premature delivery.
Abstract: We analyze the relationship between prenatal WIC participation and birth outcomes in New York City from 1988—2001. The analysis is unique for several reasons. First, we have over 800,000 births to women on Medicaid, the largest sample ever used to analyze prenatal participation in WIC. Second, we focus on measures of fetal growth distinct from preterm birth, since there is little clinical support for a link between nutritional supplementation and premature delivery. Third, we restrict the primary analysis to women on Medicaid who have no previous live births and who initiate prenatal care within the first four months of pregnancy. Our goal is to lessen heterogeneity between WIC and non-WIC participants by limiting the sample to highly motivated women who have no experience with WIC from a previous pregnancy. Fourth, we analyze a large sub-sample of twin deliveries. Multifetal pregnancies increase the risk of anemia and fetal growth retardation and thus may benefit more than singletons from nutritional supplementation. We find no relationship between prenatal WIC participation and measures of fetal growth among singletons. We find a modest pattern of association between WIC and fetal growth among U.S.-born Black twins. Our findings suggest that prenatal participation in WIC has had a minimal effect on adverse birth outcomes in New York City. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: It is found that increasing the price of cigarettes would substantially decrease the number of young adults who progress into higher intensities of smoking, and private worksite restrictions and restrictions in other public places are found to decrease moderate smoking uptake among young adults.
Abstract: In the wake of significant budget shortfalls, 37 states and the District of Columbia have recently increased cigarette excise taxes to boost revenues. This study examines the impact of increasing the price of cigarettes, which will occur as a consequence of cigarette excise tax increases, and implementing restrictions on smoking in private worksites, restaurants, government worksites, healthcare facilities, and other public places on young adult smoking progression. This paper employs nationally representative longitudinal data on young adults from the Monitoring the Future Surveys matched with information on site-specific prices and smokefree air laws. The estimates clearly indicate that increasing the price of cigarettes would substantially decrease the number of young adults who progress into higher intensities of smoking. In addition, private worksite restrictions and restrictions on smoking in other public places are found to decrease moderate smoking uptake among young adults.
TL;DR: In this article, an analysis of Texas counties that dealt with these problems shows that the Texas crime drop was largely due to increases in the jail and prison population; property crime also dropped due to increasing in real wages and wealth and in public order arrests.
Abstract: Crime went down throughout the U.S. in the 1990s. Potential explanations include demographic shifts, improved economic opportunities, changes in drug markets, evolving police strategies, and an increasing prison population. Previous attempts to parcel out responsibility among these explanations are unpersuasive. Some do not consider all of the explanations, others rely on highly aggregated data, still others confuse cause and effect. An analysis of Texas counties that deals with these problems shows that the Texas crime drop was largely due to increases in the jail and prison population; property crime also dropped due to increases in real wages and wealth and in public order arrests. Further prison construction would not be cost-effective in Texas due to declining marginal returns, but direct interventions to improve economic opportunities or make police work more proactive may be. © 2005 by the Association for Public Policy Analysis and Management.
TL;DR: In this article, the authors present a theoretical model of managerial objectives that yields testable hypotheses, which they test using 2001 data on 190,000 American nonprofits and show that while there is substantial variation between different types of nonprofits, they generally approach a service maximization objective, but maintain fundraising budgets that are insufficient to meet this objective.
Abstract: The objectives of nonprofit managers are not immediately apparent. Indeed, nonprofits may seek to maximize their level of service or their budgets, or they may have undefined or unstable objectives. This paper presents a theoretical model of managerial objectives that yields testable hypotheses, which I test using 2001 data on 190,000 American nonprofits. While there is substantial variation between different types of nonprofits, they generally approach a service maximization objective, but maintain fundraising budgets that are insufficient to meet this objective. These findings have significant implications for policy and nonprofit management. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: The authors used quasi-experimental methods to estimate the impact of whole-school reform on students' reading performance in New York City, where various reform programs were adopted in dozens of troubled elementary schools in the mid-1990s.
Abstract: Thousands of schools around the country have implemented whole-school reform programs to boost student performance. This paper uses quasi-experimental methods to estimate the impact of whole-school reform on students' reading performance in New York City, where various reform programs were adopted in dozens of troubled elementary schools in the mid-1990s. This paper complements studies based on random assignment by examining a broad-based reform effort and explicitly accounting for implementation quality. Two popular reform programs—the School Development Program and Success for All—were not found to significantly increase reading scores but might have been if they had been fully implemented. The More Effective Schools program was found to boost reading scores, but this effect seems to disappear when the program “trainers” leave the school. © 2005 by the Association for Public Policy Analysis and Management.
TL;DR: In this paper, the effects of state research and development tax credits on private R&D expenditure in the states were examined. And the statistical results showed that the establishment of state R&DC credit programs is effective in stimulating more industrial R&DI expenditure.
Abstract: This is a cross-state empirical study which examines the effects of state research and development (R&D) tax credits on private R&D expenditure in the states. Other explanatory variables include federal R&D subsidies, public services in higher education and R&D-targeted programs as well as other control variables. The statistical result shows that the establishment of state R&D credit programs is effective in stimulating more industrial R&D expenditure. In addition, state services in higher education and R&D-targeted programs also matter in private decision of R&D investment. This policy assessment sends a positive message to state policymakers because it shows the great potential in using R&D policy instruments to promote innovation-based economic development. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: In this paper, the authors examined the importance of parental influences, prices, and tobacco control policies on the smoking behavior of youths and found that specific parental influences (such as communication/bonding, limit-setting with regard to free time, home smoking rules, and parental smoking behavior) and the extent to which teenagers value their parents' opinions play a significant role in youth smoking decisions.
Abstract: This paper jointly examines the importance of parental influences, prices, and tobacco control policies on the smoking behavior of youths. Data are drawn from the Audits & Surveys (A&S) 1996 survey of high school students across the United States from “The Study of Smoking and Tobacco Use Among Young People” to examine the impact of parental influences on the probability of youth smoking in the context of both specific observable parenting behaviors and in terms of youths' perceptions of the importance of their parents' opinions. The key finding is that specific parental influences (such as communication/bonding (extent of discussions about daily issues between parent/adult and child), limit-setting with regard to free time, home smoking rules, and parental smoking behavior) and the extent to which teenagers value their parents' opinions play a significant role in youth smoking decisions. Our results by age reveal that specific modifications related to improving communication channels and implementing home smoking rules and more general changes that improve the quality of the parent-child relationship so teens place a higher value on their parents' opinions are likely to be particularly effective in the early teen years. © 2005 by the Association for Public Policy Analysis and Management.
TL;DR: The authors found that the elasticity of the welfare caseload with respect to the minimum wage is 0.20, which suggests that minimum wages are not an efficient policy for facilitating the transition from welfare to work.
Abstract: Although minimum wages are advocated as a policy that will help the poor, few studies have examined their effect on poor families. This paper uses variation in minimum wages across states and over time to estimate the impact of minimum wage legislation on AFDC caseloads, thus directly assessing whether minimum wages benefit a group they are intended to help. We find that the elasticity of the welfare caseload with respect to the minimum wage is 0.20. This suggests that minimum wages are not an efficient policy for facilitating the transition from welfare to work. We appreciate the financial support of the Joint Center for Poverty Research and the U.S. Department of Agriculture. We would also like to thank Mark Smith for providing us with the political variables, Aaron Yelowitz for supplying us with the Medicaid data, and Matthew Harrington for helping us collect and analyze other state-level data. We also thank Michael Baker, David Ellwood, Oscar Jorda, Peggy O’BrienStrain, Anne Piehl, Robert Plotnick, Deborah Reed, Kim Rueben, Mark Smith, James Ziliak and participants in the Bay Area Labor Economists workshop, the UC-Davis Applied Microeconomics seminar, the NBER Universities Research Conference and the Public Policy Institute of California brown bag series, for their suggestions. Tracy Turner provided outstanding research assistance.
TL;DR: Bitler and Currie as mentioned in this paper made sense of competing claims about the efficacy of the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) on pregnancy and birth outcomes.
Abstract: have asked us to help readers make sense of the competingclaims about the efficacy of the Special Supplemental Nutrition Program forWomen, Infants and Children (WIC) on pregnancy and birth outcomes that haveappeared in the journal over the past three issues: The paper by Marianne P. Bitlerand Janet Currie in
TL;DR: In this paper, the authors examine the effect of such policies using an institutional framework, designed to illustrate how factors both from inside and outside of academia influence the decision to patent university research, and find passage of the Bayh-Dole Act spurred university patenting, but did not induce additional applied research funding.
Abstract: Over the past 20 years, the number of patents assigned to universities has increased dramatically. This increase coincided with several policy initiatives, such as the Bayh-Dole Act of 1980, designed to foster technology transfer between universities and the private sector. This paper examines the effect of such policies using an institutional framework, designed to illustrate how factors both from inside and outside of academia influence the decision to patent university research. We find passage of the Bayh-Dole Act spurred university patenting, but did not induce additional applied research funding. Thus, Bayh-Dole fostered technology transfer, but did not result in more applied research at universities. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: The authors found that instructors' looks are not important determinants of their student evaluations of teaching (SET) results, and concluded that earlier findings indicating that instructor appearance is important are likely due to omitted variable bias.
Abstract: Some studies suggest that instructors' looks are important determinants of their Student Evaluations of Teaching (SET) results. Yet the studies examining this proposition leave out many independent variables that have been found to be important determinants of SETs in the SET literature. This study adds in most such factors and finds that, controlling for these other factors, attractiveness has no effect in our data. We conclude that earlier findings indicating that instructor appearance is important are likely due to omitted variable bias. © 2005 by the Association for Public Policy Analysis and Management
TL;DR: In this article, tax law and income distribution changes have separately contributed to the changes in tax progressivity over time, and also how a specific pre-tax distribution of income affects the equalizing ability of a given tax change.
Abstract: In this paper, we determine how tax law and income distribution changes have separately contributed to the changes in tax progressivity over time, and also how a specific pre-tax distribution of income affects the equalizing ability of a given tax change. We use information from the Current Population Survey for years that follow immediately after significant tax law changes or after the full enactment of these changes to measure the effect of income taxes on income distribution for selected years over the period 1978 to 1998. We find that, even when account is taken of the induced effect of changes in federal income tax laws on pre-tax income, the individual income tax structure has been less successful in equalizing after-tax income since the 1980s and into the early 1990s. We also find that a given tax law's equalizing effect on the distribution of income is significantly affected by the pre-tax distribution of income. © 2005 by the Association for Public Policy Analysis and Management.
TL;DR: The Kaldor-Hicks tableau format can serve as a heuristic aid for teaching microeconomics-based policy analysis, and offer insight to policy analysts and decisionmakers beyond conventional efficiency analysis as discussed by the authors.
Abstract: This note describes the Kaldor-Hicks (KH) tableau format as a framework for distributional accounting in cost-benefit analysis and policy evaluation The KH tableau format can serve as a heuristic aid for teaching microeconomics-based policy analysis, and offer insight to policy analysts and decisionmakers beyond conventional efficiency analysis © 2005 by the Association for Public Policy Analysis and Management
TL;DR: The paper argues that Joyce et al. overstate the degree of medical consensus that exists over the question of whether or not prenatal intervention can affect the probability of preterm birth, and argues that WIC should only affect birth weight through effects on fetal growth.
Abstract: Journal of Policy Analysis and Management, Vol. 24, No. 4, 687–690 (2005) © 2005 by the Association for Public Policy Analysis and Management Published by Wiley Periodicals, Inc. Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/pam.20132 Many previous studies of WIC conclude that “WIC works,” but in their article in this issue, Ted Joyce, Diane Gibson, and Silvie Colman come to the opposite conclusion (Joyce, Gibson, & Colman, 2005). They arrive at this position even though their actual estimates are consistent with those of previous studies. For example, like our largescale study of women on Medicaid in 19 states (Bitler & Currie, 2005), they find that prenatal participation in the WIC program reduces the incidence of low birth weight and preterm birth. We also find that WIC participation is associated with decreases in birth weight adjusted for gestation, the nights an infant or woman was in the hospital at delivery, and positively associated with weight gain during pregnancy, gestation, birthweight, and use of prenatal care during the first trimester. Why then are Joyce, Gibson, and Colman’s conclusions so different than those of previous authors? The crux of the matter is that Joyce et al. reject the idea that WIC could have any effect on preterm birth, while neglecting discussion of other possible positive impacts of WIC. Hence, they reason that any estimated effects of WIC on preterm birth reflect selection effects in the data and ought to be discounted out of hand. Further, they argue that WIC should only affect birth weight through effects on fetal growth, and they do not find any effects on fetal growth (except in their subsample of Black twins). We think that this line of reasoning is flawed on several counts, and perhaps too narrowly focused. First, Joyce et al. overstate the degree of medical consensus that exists over the question of whether or not prenatal intervention can affect the probability of preterm birth. They cite several studies describing specific clinical interventions that were not effective in preventing preterm births. But the clinical literature also suggests, for example, that smoking causes preterm labor, so that interventions that were effective in reducing smoking might be expected to have an effect on prematurity (compare Werler, 1997).1 Similarly, gestational diabetes is a common complication of pregnancy that can lead to preterm birth, but it is easily controlled if it is detected early (Xiong, Saunders, Wang, & Demianczuk, 2001). Maternal infections are thought to account for up to a third of preterm births, and some trials have shown that treatment of high-risk women for specific infections can increase the length of pregnancy (Gibbs & Eschenbach, 1997; Goldenberg, Hauth, & Andrews, 2000; Locksmith & Duff, 2001), while others have shown a possible positive impact of treatment for wider groups of women (Lamont, Duncan, Mandal, & Bassett, 2003; Kiss, Petricevic, & Husslein, 2004; Ugwumadu, Manyonda, Reid, & Hay,