measuring the impacts of teachers ii teacher value added and student outcomes in adulthood abstract are teachers impacts on students test scores value added a good measure of their quality this question has sparked debate partly because of a lack of evidence on whether high value ad

forms of trust and conditions for their stability of the three principal approaches to trust we decided to investigate in greater detail the one in which trust is regarded as a belief that the individuals involved hold about a relationship trust was defined as a delegatory relationship based on anticipation of the delegatee s behaviour we reached four main conclusions first the solution to the problem posed by the indeterminacy of trust lies in the differentiation and hierarchisation of the various forms of trust contractual organisational and tacit on the basis of their degree of irreversibility and stability second contractual trust is unstable because it comes up against the problem of guarantees of individual intentions this leads to the third conclusion rational evaluation by individuals cannot by itself establish trust which is based on collective beliefs practices and rules fourth we identified two conditions for the stability of trust the creation of irreversibilities through adherence to a rule and the creation of a confidence interval within which different interpretations of contradictory individual strategies are tolerated thus the viability of the various forms of trust depends on the ability of institutions and organisations to create rules that are likely when applied to produce an interval in which tolerance of mutual intentions is the norm these analyses of trust hence highlight the role of time and period of time in the notion of trust

does public insurance crowd out private insurance the cost of expanding public sector health programs depends critically on the extent to which public eligibility will cover just the uninsured or will crowd out existing private insurance coverage we estimate the extent of crowd out arising from the expansions of medicaid to pregnant women and children over the 1987 1992 period we estimate that approximately 50 percent of the increase in medicaid coverage was associated with a reduction in private insurance coverage this occurred largely because employees took up employer based insurance less frequently there is also some evidence that employers contributed less for insurance and that workers dropped coverage of dependents

the regional geography of corporate patenting in information and communications technology ict domestic and foreign dimensions in the new techno socio economic conditions characterized by an increasing reduction of temporal and spatial barriers and further globalization of economic activity paradoxically geography seems to matter more than ever before this particularly applies to science based industries e g information and communications technology ict where links between corporate competitors and firm university and user producer relationships are crucial in the development and adoption of new flexible technologies using us patents granted to the largest european electronic firms this paper looks at the interplay between the patenting by domestic and european foreign electronics companies of research and development carried out in ict fields in german uk and italian regions the findings suggest that patenting is attracted to existing areas of industrial strength taking a form of cumulative causation nonetheless policy measures may be successful in reversing the trend sous de nouvelles conditions techno et soc

the effect of medicaid expansions for low income children on medicaid participation and private insurance coverage evidence from the sipp abstract we examine medicaid enrollment and private coverage loss following expansions of medicaid eligibility we attempt to replicate cutler and gruber s q j econ 111 1996 391 results using the survey of income and program participation sipp and find smaller rates of take up and little evidence of crowding out we find that some of the difference in results can be attributed to different samples and recall periods in the data sets used extending the previous literature we find that take up is slightly increased if a child s siblings are eligible and with time spent eligible focusing on children whose eligibility status changes during the sample we estimate smaller take up effects we find little evidence of crowding out in any of our extensions

the impact of medicaid on labor market activity and program participation evidence from the oregon health insurance experiment united states dept of health and human services assistant secretary for planning and evaluation

competing technologies the learning curve and rational expectations abstract the problem of choice between several variants of a technology subject to dynamic learning economies is examined in a rational expectations model with overlapping adopters it is shown that even with rational expectations the long term market outcome depends sensitively on the pattern of early chance events and that only one variant of the technology will come to dominate the market in the long run this variant need not be the one which is socially optimal or most promising technically

a failure inducement model of research and development expenditure abstract empirical evidence for the schumpeterian suggestion of a positive relationship between profitability and innovative effort is slim in fact the opposite is often suggested an alternative failure inducement hypothesis argues that firms make innovative efforts when performance falls below a minimum threshold resulting in a negative relationship between profitability and r d expenditures data on r d expenditures in italian industry in the early 1980s a period of severe economic crisis show that both hypotheses are relevant for firms whose profits are well above or well below average respectively

early life health interventions and academic achievement this paper studies the effect of improved early life health care on mortality and long run academic achievement in school we use the idea that medical treatments often follow rules of thumb for assigning care to patients such as the classification of very low birth weight vlbw which assigns infants special care at a specific birth weight cutoff using detailed administrative data on schooling and birth records from chile and norway we establish that children who receive extra medical care at birth have lower mortality rates and higher test scores and grades in school these gains are in the order of 0 15 0 22 standard deviations

using differences in knowledge across neighborhoods to uncover the impacts of the eitc on earnings we develop a new method of estimating the impacts of tax policies that uses areas with little knowledge about the policy s marginal incentives as counterfactuals for behavior in the absence of the policy we apply this method to characterize the impacts of the earned income tax credit eitc on earnings using administrative tax records covering all eitc eligible lers from 19962009 we begin by developing a proxy for local knowledge about the eitc schedule the degree of sharp bunching at the exact income level that maximizes eitc refunds by individuals who report self employment income the degree of self employed sharp bunching varies signi cantly

stepping on a rake the role of fiscal policy in the inflation of the 1970s abstract the inflation of the 1970s in the us is often discussed as if the only type of policy action that could have prevented the inflation were monetary policy actions and the only type of policy errors that might have induced the inflation were monetary policy errors yet fiscal policy underwent dramatic shifts in the 1970s and economic theory makes clear that in an environment of uncertainty about future fiscal policy monetary policy instruments may lose potency or have perverse effects this paper documents the vagaries of fiscal policy in this period and argues that people at the time must have been uncertain about fiscal policy s future course it also lays out a theoretical framework for understanding the effects of fiscal uncertainties on monetary policy and shows that fiscal variables have predictive value in dynamic models even if traditional monetary policy indicators are included in the system

regional variations in production network externalities capello r and nijkamp p 1996 regional variations in production network externalities reg studies 30 225 237 in the present paper the main area of analysis is the concept of network externalities and its interpretation from a theoretical conceptual and empirical point of view a conceptual framework is built on the proposition that network externalities are one of the decisive reasons for entering a telecommunication network since externality mechanisms arise at the user side and impact on the demand function they can be labelled consumption network externalities however this paper goes a step further than the recent literature by claiming that telecommunication networks are not only governed by consumption network externalities but also generate production network externalities since their advantages may be measured in terms of the performance of firms and regions the paper presents a conceptual model on the role network externality plays on the performance of firms and regions a metho

employment hysteresis from the great recession this paper uses us local areas as a laboratory to test for long term impacts of the great recession in administrative longitudinal data i estimate that exposure to a 1 percentage point larger 200

state abortion rates the impact of policies providers politics demographics and economic environment abstract this paper uses data on abortion rates by state from 1974 1988 to estimate two stage least squares models with fixed state and year effects restrictions on medicaid funding for abortion are correlated with lower abortion rates in state and higher rates among nearby states a maximal estimate suggests that 19 25 of the abortions among low income women that are publicly funded do not take place after funding is eliminated parental notification laws for teen abortions do not significantly affect aggregate abortion rates a larger number of abortion providers in a state increases the abortion rate primarily through inducing cross state travel

technology adoption in the presence of network externalities we analyze technology adoption in industries where network externalities are significant the pattern of adoption depends on whether technologies are sponsored a sponsor is an entity that has property rights to the technology and hence is willing to make investments to promote it key findings include the following 1 compatibility tends to be undersupplied by the market but excessive standardization can occur 2 in the absence of sponsors the technology superior today has a strategic advantage and is likely to dominate the market 3 when one of two rival technologies is sponsored that technology has a strategic advantage and may be adopted even if it is inferior 4 when two competing technologies both are sponsored the technology that will be superior tomorrow has a strategic advantage

health insurance and mortality experimental evidence from taxpayer outreach we evaluate a randomized pilot study in which the irs sent informational letters to 3 9 million taxpayers who paid a tax penalty for lacking health insurance coverage under the affordable care act drawing on administrative data we study the effect of the intervention on taxpayers subsequent health insurance enrollment and mortality we find the intervention led to increased coverage in the two years following treatment and that this additional coverage reduced mortality among middle aged adults over the same time period our results provide the first experimental evidence that health insurance reduces mortality

the oregon health insurance experiment evidence from the first year in 2008 a group of uninsured low income adults in oregon was selected by lottery to be given the chance to apply for medicaid this lottery provides an opportunity to gauge the effects of expanding access to public health insurance on the health care use financial strain and health of low income adults using a randomized controlled design in the year after random assignment the treatment group selected by the lottery was about 25 percentage points more likely to have insurance than the control group that was not selected we find that in this first year the treatment group had substantively and statistically significantly higher health care utilization including primary and preventive care as well as hospitalizations lower out of pocket medical expenditures and medical debt including fewer bills sent to collection and better self reported physical and mental health than the control group

fiscal stabilization vs passivity fiscal policies that stabilize debt may not provide the fiscal backing necessary for monetary policy to successfully target inflation appropriate backing is provided by passive fiscal behavior understanding the distinction between stabilizing and passive fiscal policies is central to the design of fiscal rules

the long run impact of cash transfers to poor families lleras muney we estimate the long run impact of cash transfers to poor families on children s longevity educational attainment nutritional status and income in adulthood to do so we collected individual level administrative records of applicants to the mothers pension program the first government sponsored welfare program in the united states 1911 1935 and matched them to census wwii and death records male children of accepted applicants lived one year longer than those of rejected mothers they also obtained onethird more years of schooling were less likely to be underweight and had higher income in adulthood than children of rejected mothers jel i12 i14 i18 i32 i38 j16 n32

the effects of exposure to better neighborhoods on children new evidence from the moving to opportunity experiment the moving to opportunity mto experiment offered randomly selected families housing vouchers to move from high poverty housing projects to lower poverty neighborhoods we analyze mto s impacts on children s long term outcomes using tax data we find that moving to a lower poverty neighborhood when young before age 13 increases college attendance and earnings and reduces single parenthood rates moving as an adolescent has slightly negative impacts perhaps because of disruption effects the decline in the gains from moving with the age when children move suggests that the duration of exposure to better environments during childhood is an important determinant of children s long term outcomes jel i31 i38 j13 r23 r38

how does your kindergarten classroom affect your earnings evidence from project star in project star 11 571 students in tennessee and their teachers were randomly assigned to classrooms within their schools from kindergarten to third grade this article evaluates the long term impacts of star by linking the experimental data to administrative records we first demonstrate that kindergarten test scores are highly correlated with outcomes such as earnings at age 27 college attendance home ownership and retirement savings we then document four sets of experimental impacts first students in small classes are significantly more likely to attend college and exhibit improvements on other outcomes class size does not have a significant effect on earnings at age 27 but this effect is imprecisely estimated second students who had a more experienced teacher in kindergarten have higher earnings third an analysis of variance reveals significant classroom effects on earnings students who were randomly assigned to higher quality classrooms in grades k 3 as measured by classmates end of class test scores have higher earnings college attendance rates and other outcomes finally the effects of class quality fade out on test scores in later grades but gains in noncognitive measures persist

a unified welfare analysis of government policies we conduct a comparative welfare analysis of 133 historical policy changes over the past half century in the united states focusing on policies in social insurance education and job training taxes and cash transfers and in kind transfers for each policy we use existing causal estimates to calculate both the benefit that each policy provides its recipients measured as their willingness to pay and the policy s net cost inclusive of long term impacts on the government s budget we divide the willingness to pay by the net cost to the government to form each policy s marginal value of public funds or its mvpf comparing mvpfs across policies provides a unified method of assessing their impact on social welfare our results suggest that direct investments in low income children s health and education have historically had the highest mvpfs on average exceeding 5 many such policies have paid for themselves as governments recouped the cost of their initial expenditures through additional taxes collected and reduced transfers we find large mvpfs for education and health policies amongst children of all ages rather than observing diminishing marginal returns throughout childhood we find smaller mvpfs for policies targeting adults generally between 0 5 and 2 expenditures on adults have exceeded this mvpf range in particular if they induced large spillovers on children we relate our estimates to existing theories of optimal government policy and we discuss how the mvpf provides lessons for the design of future research

long run impacts of childhood access to the safety net a growing economics literature establishes a causal link between in utero shocks and health and human capital in adulthood most studies rely on extreme negative shocks such as famine and pandemics we are the first to examine the impact of a positive and policy driven change in economic resources available in utero and during childhood in particular we focus on the introduction of a key element of the u s safety net the food stamp program which was rolled out across counties in the u s between 1961 and 1975 we use the panel study of income dynamics to assemble unique data linking family background and county of residence in early childhood to adult health and economic outcomes the identification comes from variation across counties and over birth cohorts in availability of the food stamp program our findings indicate that the food stamp program has effects decades after initial exposure specifically access to food stamps in childhood leads to a significant reduction in the incidence of metabolic syndrome obesity high blood pressure and diabetes and for women an increase in economic self sufficiency overall our results suggest substantial internal and external benefits of the safety net that have not previously been quantified

long term impacts of childhood medicaid expansions on outcomes in adulthood we use administrative data from the internal revenue service to examine long term impacts of childhood medicaid eligibility expansions on outcomes in adulthood at each age from 19 to 28 greater medicaid eligibility increases college enrolment and decreases fertility especially through age 21 starting at age 23 females have higher contemporaneous wage income although male increases are imprecise together both genders have lower mortality these adults collect less from the earned income tax credit and pay more in taxes cumulatively from ages 19 to 28 at a 3 discount rate the federal government recoups 58 cents of each dollar of its investment in childhood medicaid

worms at work long run impacts of a child health investment this study estimates long run impacts of a child health investment exploiting community wide experimental variation in school based deworming the program increased labor supply among men and education among women with accompanying shifts in labor market specialization ten years after deworming treatment men who were eligible as boys stay enrolled for more years of primary school work 17 more hours each week spend more time in nonagricultural self employment are more likely to hold manufacturing jobs and miss one fewer meal per week women who were in treatment schools as girls are approximately one quarter more likely to have attended secondary school halving the gender gap they reallocate time from traditional agriculture into cash crops and nonagricultural self employment we estimate a conservative annualized financial internal rate of return to deworming of 32 and show that mass deworming may generate more in future government revenue than it costs in subsidies

the city network paradigm measuring urban network externalities in recent years network behaviour has been analysed extensively as the emerging model for economic growth by network behaviour a metaphor for co operative behaviour among individuals corporate

inefficient standard adoption inertia and momentum revisited i introduction since the establishment of the theory of network effects economists have been concerned with the question of whether a market with network effects will tend to settle on the socially optimal standard it has been postulated that markets may exhibit excess inertia once a technological standard is in place a new superior standard may not displace it because of installed base effects alternatively markets may exhibit excess momentum consumers may adopt a new standard too quickly ignoring the stranding effect they are having on previous users similar issues arise in the adoption of language and social norms the literature has investigated various conditions under which one of these inefficiencies arises such inefficiencies are of particular concern for open technologies such as the qwerty and dvorak keyboards 1 the situation is somewhat different when individual firms own standards in that case a simple argument seems to indicate that there is no possibility that an inefficient standard will persist if a new standard is superior in any objective sense there are gains to be made from switching to it once the standard has been adopted the firm can appropriate these gains therefore the firm has incentive to lower the initial price enough to induce adoption of the standard the preceding argument is made in liebowitz and margolis 1999 and repeated in spulber 2002 spulber expresses a general skepticism about the likelihood of inefficiencies when property rights are defined and markets exist critics might claim that previous models that imply inefficient standard adoption are unrealistic in some way and that if such models were modified slightly the inefficiency would disappear i reconsider the issue of inefficient standard adoption using a parsimonious yet compelling model assuming only that there are successive generations of finitely lived consumers that preferences are heterogeneous and that there are network effects among users adoption decisions can be inefficient this is true even if consumers can coordinate efficiently within a generation and a firm can act as a coordinating device across generations the model presented here generates some of the same results found in other papers collectively but in a more general setting and with more robust results if there is an established standard and a superior alternative emerges no single generation of consumers will be willing to switch to the new standard if the switching cost the loss of network benefit from breaking with past users is too high it may be that the benefits to future generations of consumers are large enough that from a social standpoint it would be efficient for one generation to adopt the new standard even if it is privately optimal for that generation to retain the old standard on the other hand the current generation considers only its own switching cost and not the cost it imposes on the previous generation leading to potential overadoption of new technology even for proprietary standards it is not clear that the incentive of the firm to induce adoption matches the social incentive in particular if consumer preferences are heterogeneous the firm will not be able to price in such a way to extract all of the additional surplus gained from the new standard on the other hand the firm will be able to appropriate some of the surplus generated by the network effect itself which is present for any standard and thus does not affect the social incentive to change standards it is not possible to address this issue with a two period model as in some of the previous literature see for example choi 1994 choi and thum 1998 katz and shapiro 1986 if a new technology is introduced in the second period but then the game ends the welfare of future generations of consumers is neglected 2 this article also differs from previous infinite horizon models of technology adoption

induced adoption and externalities in the regional diffusion of information technology antonelli c 1990 induced adoption and externalities in the regional diffusion of information technology reg studies 24 31 40 information technology can be considered as a set of complex radical innovations which continues to evolve and has a major impact both within the plant and the office in such a context its regional diffusion is likely to be determined by relevant externalities together with the effects of a wage induced process of localized technological change and adoption data on the territorial distribution of fax machines and modems show that the levels of diffusion of information technology in italy is highly uneven favouring central regions endowed with higher levels of fixed and human capital and consequently income the econometric analysis confirms that diffusion levels of both fax and modems across provinces are significantly associated with the level of wages as is to be expected from the induced adoption hypothesis and from the existence of external factors such as the presence

bounding causal effects using data from a contaminated natural experiment analysing the effects of teenage childbearing in this paper we consider what can be learned about causal effects when one uses a contaminated instrumental variable in particular we consider what inferences can be made about the causal effect of teenage childbearing on a teen mother s subsequent outcomes when we use the natural experiment of miscarriages to form an instrumental variable for teen births miscarriages might not meet all of the conditions required for an instrumental variable to identify such causal effects for all of the observations in our sample however it is an appropriate instrumental variable for some women namely those pregnant women who experience a random miscarriage although information from typical data sources does not allow one to identify these women we show that one can adapt results from horowitz and manski 1995 on identification with data from contaminated samples to construct informative bounds on the causal effect of teenage childbearing we use these bounds to re examine the effects of early chilbearing on the teen mother s subsequent educational and labour market attainment as considered in hotz mcelroy and sanders 1995a 1995b consistent with their study these bounds indicate that women who have births as teens have higher labour market earnings and hours worked compared to what they would have attained if their childbearing had been delayed

technology adoption and the emergence of regional asymmetries the model explains the emergence of asymmetric productive structures among regions based on adoption of a quality improving technology firms products are diierentiated both in location and quality location is given we characterize symmetric and asymmetric equilibria of the two stage game in price and adoption asymmetric equilibria display partial adoption frequencies and regular geographical patterns of adoptions the asymmetry of the economy has often a reverse u shaped relation with the innovation size market integration is an obstacle for the full adoption of the new technology and favours the emergence of regional asymmetries i introduction regional income inequalities in the european community are very large the following gures reported by dunford 1993a f rom the regio database give an idea about their magnitude in 1989 per capita output in nuts 2 1 regions measured in purchasing power standards pps varied between 177 to 40 of the ec average or between 199 and 26 if measured in ecu over 18 of the population of the ec lived in areas with a per capita gdp of less than 75 of the community average a further 36 lived in areas with a per capita gdp below the community average at the other end of the distribution 10 of the population of the community lived in areas with an average per capita gdp 53 above the community average these leading regions form an area also de ned as the blue banana which extends from greater london to groningen in the netherlands hamburg darmstadt bremen oberbayern and stuttgart in germany the i le de france in france down to lombardia and emilia romagna in italy

the effect of child health insurance access on schooling evidence from public insurance expansions although a sizable literature analyzes the effects of public health insurance programs on short run health outcomes little prior work has examined their long term effects we examine the effects of public insurance expansions among children in the 1980s and 1990s on their future educational attainment we find that expanding health insurance coverage for low income children increases the rate of high school and college completion these estimates are robust to only using federal medicaid expansions and mostly are due to expansions that occur when the children are not newborns our results indicate that the long run benefits of public health insurance are substantial

the economics of convention c onventions regulate much of economic and social life yet they have received surprisingly little attention from economists by a convention we mean a pattern of behavior that is customary expected and self enforcing everyone conforms everyone expects others to conform and everyone has good reason to conform because conforming is in each person s best interest when everyone else plans to conform lewis 1969 familiar examples include following rules of the road adhering to conventional codes of dress and using words with their conventional meanings conventions with direct economic implications include species of money and credit industrial and technological standards accounting rules and forms of economic contracts indeed it would scarcely be an exaggeration to say that almost all economic and social institutions are governed to some extent by convention the main feature of a convention is that out of a host of conceivable choices only one is actually used this fact also explains why conventions are needed they resolve problems of indeterminacy in interactions that have multiple equilibria indeed from a formal point of view we may define a convention as an equilibrium that everyone expects in interactions that have more than one equilibrium the economic significance of conventions is that they reduce transaction costs imagine the inconvenience if whenever two vehicles approached one another the important exceptions are sugden 1986 and ullman margalit 1977 the interested reader might also refer to the symposium on social norms that appeared in the fall 1989 issue of this journal with articles by sugden 1989 and elster 1989

will extending medicaid to two parent families encourage marriage several welfare programs in the united states restrict eligibility to single parent families this paper asks whether eliminating this restriction for medicaid encourages marriage i identify medicaid s effect through a series of health insurance reforms that were passed in the 1980s and 1990s targeting young children these reforms were associated with an increase in the probability of marriage of 1 7 percentage points while the expansions offered some incentives to become married they also created other incentives to become divorced known as the independence effect after controlling for the outflows from marriage due to the independence effect the estimated effect increases by 10 percent

does welfare inhibit success the long term effects of removing low income youth from the disability rolls i estimate the effects of removing low income youth with disabilities from supplemental security income ssi on their earnings and income in adulthood using a regression discontinuity design based on a 1996 policy change in age 18 medical reviews i find that youth who are removed from ssi at age 18 recover one third of the lost ssi cash income in earnings ssi youth who are removed and stay off ssi earn on average 4 400 annually and they lose 76 000 in present discounted observed income over the 16 years following removal relative to those who do not receive a review jel i30 i38 j14 supporters of welfare programs defend them as vital lifelines for those who face barriers to work while critics charge that these programs create perverse incentives to qualify and perpetuate dependency encapsulating this debate is the controversy over the us supplemental security income ssi program a program that provides cash payments and medicaid eligibility to low income children and adults with disabilities and the aged elderly after three decades of rapid expansion ssi is now the largest nonwork based cash welfare program in the united states paying about 50 billion each year to 8 million recipients including 1 3 million children 1 ssi has been singled out by policymakers and the media for potential perverse incentives

health insurance eligibility utilization of medical care and child health two economists applied data from the current population survey and the national health interview survey and state level data on child mortality to a simulation model of utilization of medical care that varies only with the states legislative environment to examine the utilization of medical care and health effects of medicaid eligibility on low income children the models took into consideration the recent expansions of medicaid to low income children 38 of those ineligible for medicaid in 1984 who became eligible due to changes during 1984 1992 were uninsured between 1984 and 1992 expansions of the medicaid program increased the proportion of children eligible for medicaid almost two fold 16 1 vs 31 2 yet coverage rates were always lower than eligibility rates 13 2 vs 16 1 in 1984 and 20 3 vs 31 2 in 1992 and the increase in coverage rates was only about 50 of the increase in eligibility rates during 1984 1992 the probability that a child was eligible for medicaid increased the probability of health insurance coverage by 29 77 when the model considered bias in variables e g a recession in a state the take up rate was only 22 73 nevertheless medicaid markedly increased use of medical care for example eligibility for medicaid increased the likelihood of making a visit to a physicians office in the last two weeks by about 50 it also increased the probability of a child visiting the hospital suggesting inefficiency in the way that providers deliver care to medicaid enrollees medicaid eligibility had a significant effect on reducing child mortality the 15 1 percentage point increase in eligibility during 1984 1992 reduced child mortality by 4 5 when the researchers examined parent assessed subjective health measures medicaid eligibility had no effect on child health medicaid eligibility reduced race and education based disparities in the number of visits and racial differences in mortality yet it may actually intensify current disparities in health care delivery site