Dragon Children: Identifying the Causal Effect of the First Child on Female Labour Supply with the Chinese Lunar Calendar*

Instrumental variables (IV) estimates of the effect of fertility on female labour supply have only been able to identify the causal effect of second and higher parity children. This study uses exogenous variation in fertility caused by the Chinese lunar calendar to identify the effect of the first child. Additionally, weighting formulas are presented to interpret IV estimates as weighted average treatment effects in the case of multiple endogenous variables, which are useful when children vary in intensity by both number and age. The effect of the first child is found to be much greater than that of other children.     

Graduate education and long‐term inventive performance: Evidence from undergraduates' choices during recessions

Using individuals' life‐cycle invention data, we investigate how graduate education affects inventive performance and inventors' abilities to absorb and combine diverse knowledge sources. To control for the endogeneity of educational choice, we use the status of college labor markets as an instrumental variable (IV), specifically the difference between the unemployment rate and its long‐run average rate by academic field. We find that graduate education, induced by the IV, significantly enhances inventive performance and the scope of exploited knowledge, exceeding the levels implied by ordinary least squares. Graduate education can have a significant causal effect on inventive capability and performance.     

Age of Menarche,Adolescent Sexual Intercourse and Schooling Attainment of Women

We use data from the 1970 British Cohort Study to measure the effect of adolescent sexual intercourse on female schooling attainment. We emphasize the appropriate use of menarcheal age as an instrumental variable (IV) for early intercourse. Our analysis suggests that developmental trajectories vary with menarcheal age and, therefore, capturing variations in individual cognitive capacities induced by pubertal timing is crucial for the validity of the IV identification strategy. Our empirical results indicate that adolescent sexuality reduces full‐time education by approximately one year. Given that 37 percent of females in our data exited virginity in adolescence, the aggregate loss of human capital as measured by average years of female schooling could be up to one‐third of a year.     

Estimation of average treatment effects using panel data when treatment effect heterogeneity depends on unobserved fixed effects

This paper proposes a new panel data approach to identify and estimate the time-varying average treatment effect (ATE). The approach allows for treatment effect heterogeneity that depends on unobserved fixed effects. In the presence of this type of heterogeneity, existing panel data approaches identify the ATE for limited subpopulations only. In contrast, the proposed approach identifies and estimates the ATE for the entire population. The approach relies on the linear fixed effects specification of potential outcome equations and uses exogenous variables that are correlated with the fixed effects. I apply the approach to study the impact of a mother's smoking during pregnancy on her child's birth weight.     

Nonparametric inference for counterfactual means: Bias-correction,confidence sets,and weak IV

This paper supplements Manski (1990) and Manski and Pepper (2000) and contributes to the literature by introducing the concept of weak IV for the partially identified mean counterfactual outcomes when an instrumental variable (IV) or a monotone instrumental variable (MIV) is available (IV or MIV assumption respectively); developing asymptotically uniformly valid confidence sets for the counterfactual mean outcomes and average treatment effects under the assumptions; correcting biases of estimates of bounds on the counterfactual mean outcomes under the assumptions. We apply the confidence sets to further examining the effect of family intactness on a child’s high school graduation originally studied in Manski et al. (1992).     

Heterogeneous economic returns to higher education: evidence from Italy

This paper uses official Italian micro data and different methods to estimate, in the framework of potential outcomes, the marginal return to college education allowing for heterogeneous returns and for self-selection into higher education. Specifically, the paper is focused on the estimation of heterogeneity of average treatment effect (ATE) on a cohort of college and high school graduates using the 2008 survey on household, income and wealth of the Bank of Italy. Methodologically, this study was carried out by using both propensity-score-based (PS-based) methods and a new approach based on marginal treatment effects (MTE), recently proposed by Heckman and his associates as a useful strategy when the ignorability assumption may be violated. In the PS-based approach, heterogeneous treatment effects are estimated in three different manners: the traditional stratification approach (propensity score strata), the regression adjustment within propensity score strata and, finally, a non-parametric smoothing approach. In the MTE approach, the treatment effect heterogeneity across individuals is estimated in a parametric as well as a semi-parametric strategy. Our empirical analysis shows that the estimated heterogeneity is substantial: following MTE based results (quite representative of other methods) the return to college graduation for a randomly selected individual varies from as high as 20 % (for persons who would add one fifth of wage from graduating college) to as low as ?22 % (for persons who would lose from college graduation), suggesting that returns are higher for individuals more likely to attend college. Furthermore, the results of different methods show very low (point) estimates of ATE: average college returns vary from 3.5 % by the PS-smoothing method to 1.8 % by the parametric MTE method, which also leads a greater treatment effect on treated (5.5 %), a moderate, but significant sorting gain and a negligible selection bias.     

The effects of families and ability on men's education and earnings in Britain

The paper estimates the returns to education for a cohort of men born in Britain in March 1958 who have been followed since birth until the age of 33. The data used has a wealth of information on family background including parental education, social class and interest shown in the child's education as well as measures of ability. These variables are typically missing in studies looking at the returns to schooling. In the paper, we find that the average return to an additional year of full-time education for the UK men is somewhere around 5 1/2% to 6% even after correcting for the effects of measurement error. The paper also presents evidence that the returns to an additional year of schooling in the UK are heterogeneous. In particular, the paper finds some evidence that men with lower tastes for education, have significantly higher marginal returns to education. The results of the paper suggest that recent IV estimates of the returns to schooling in the UK, which exceed typical OLS estimates, may overestimate the average marginal return for the population of men as a whole.     

Human Capital Spillovers within the Workplace: Evidence for Great Britain*

In this paper, we use a unique matched worker–workplace data set to estimate the effect on own earnings of co‐workers’ education. Our results, using the 1998 GB Workplace Employee Relations Survey, show significant effects. An independent, significantly positive effect from average workplace education is evident; own earnings premia from years of education fall only slightly when controlling for workplace education. This result suggests that the social returns to education are strongly positive – working with colleagues who each had 1.2 years (1 standard deviation) of more education than the average worker, boosts own earnings by 11.1%. An additional year of any single co‐worker's education is worth about 3.2% of an additional own year of education. We also test for interactions between own and co‐worker education levels and for ‘skills incompatibility’ when worker education levels are heterogeneous. The interactions appear negative: own education is not much valued at workplaces where co‐workers’ education levels are already high. There is no evidence that workplace heterogeneity in worker education levels adversely affects own earnings. This result runs counter to theoretical predictions, and suggests that workers compete in tournaments for high‐paying jobs.     

Evaluating the effectiveness of private education across countries: a comparison of methods

This paper aims at estimating the effect of private vs. public education on pupils' achievement using the 2000 Organisation for Economic Co-operation and Development (OECD) Program for International Student Assessment (PISA) survey and taking into account the potential bias due to the existence of unobserved confounding factors. To deal with these selection biases, three methods are implemented in a comparative perspective: (1) instrumental variable (IV) regression; (2) Heckman's two-stage approach and (3) propensity score matching. This exercise underlines important divergences between the results of parametric and non-parametric estimators. All results, however, show that private education does not generate systematic benefits.     

Productivity Gains from Geographic Concentration of Human Capital: Evidence from the Cities

Based on recent theoretical developments the argument is made that the average level of human capital is a local public good. Cities with higher average levels of human capital should therefore have higher wages and higher land rents. After conditioning on the characteristics of individual workers and dwellings, this prediction is supported by data for Standard Metropolitan Statistical Areas (SMSAs) in the United States, where the SMSA average levels of formal education and work experience are used as proxies for the average level of human capital. The alternative explanations of omitted SMSA variables and self-selection are evaluated. An estimate of the effect of an additional year of average education on total factor productivity is computed.     

Why is the payoff to schooling smaller for immigrants?

To answer the question, this paper uses the Over-Required-Under Education technique, a new decomposition methodology and data on adult men from the 2000 US Census. Using the 510 three-digit occupational categories, similar patterns emerge whether the mean or mode of education in the occupation is used as the typical (required) level. The partial effect of the occupation's typical schooling level is the same for immigrants and natives. About two thirds of the smaller effect of schooling on earnings is attributable to differences by nativity in the payoffs to over/under education. The remainder is largely due to the different distributions by nativity of over/under education. Favorable immigrant selectivity, especially among the least skilled, and to a lesser extent, limited transferability of foreign schooling, is largely responsible for these patterns. A variety of tests of robustness are performed, including separate analyses for child and adult immigrants.     

A Cautionary Tale About Control Variables in IV Estimation

Many instrumental variable (IV) regressions include control variables to justify (conditional) independence of the instrument and the potential outcomes. The plausibility of conditional IV independence crucially depends on the timing when the control variables are determined. This paper works through different IV models and discusses the (conditions for the) satisfaction of conditional IV independence depending on whether the control variables are measured prior to or after instrument assignment. To illustrate the identification issues, we consider the Vietnam War draft risk as instrument either for veteran status or education to evaluate the effects of these variables on labour market and health outcomes. Our empirical analysis based on the ‘Young Men in High School and Beyond’ survey suggests that commonly used conditional IV strategies to estimate the impact of draft induced military service or education may be severely biased due to the use of improper controls.     

Bayesian inference in a correlated random coefficients model: Modeling causal effect heterogeneity with an application to heterogeneous returns to schooling

We consider the problem of causal effect heterogeneity from a Bayesian point of view. This is accomplished by introducing a three-equation system, similar in spirit to the work of Heckman and Vytlacil (1998), describing the joint determination of a scalar outcome, an endogenous “treatment” variable, and an individual-specific causal return to that treatment. We describe a Bayesian posterior simulator for fitting this model which recovers far more than the average causal effect in the population, the object which has been the focus of most previous work. Parameter identification and generalized methods for flexibly modeling the outcome and return heterogeneity distributions are also discussed.Combining data sets from High School and Beyond (HSB) and the 1980 Census, we illustrate our methods in practice and investigate heterogeneity in returns to education. Our analysis decomposes the impact of key HSB covariates on log wages into three parts: a “direct” effect and two separate indirect effects through educational attainment and returns to education. Our results strongly suggest that the quantity of schooling attained is determined, at least in part, by the individual’s own return to education. Specifically, a one percentage point increase in the return to schooling parameter is associated with the receipt of (approximately) 0.14 more years of schooling. Furthermore, when we control for variation in returns to education across individuals, we find no difference in predicted schooling levels for men and women. However, women are predicted to attain approximately 1/4 of a year more schooling than men on average as a result of higher rates of return to investments in education.     

Doubly robust uniform confidence band for the conditional average treatment effect function

In this paper, we propose a doubly robust method to estimate the heterogeneity of the average treatment effect with respect to observed covariates of interest. We consider a situation where a large number of covariates are needed for identifying the average treatment effect but the covariates of interest for analyzing heterogeneity are of much lower dimension. Our proposed estimator is doubly robust and avoids the curse of dimensionality. We propose a uniform confidence band that is easy to compute, and we illustrate its usefulness via Monte Carlo experiments and an application to the effects of smoking on birth weights.     

The demand for season of birth

We study the determinants of season of birth for married women aged 20–45 in the USA, using birth certificate and Census data. We also elicit the willingness to pay for season of birth through discrete‐choice experiments implemented on the Amazon Mechanical Turk platform. We document that the probability of a spring first birth is significantly related to mother's age, education, race, ethnicity, smoking status during pregnancy, receiving WIC (Women, Infants & Children) food benefits during pregnancy, prepregnancy obesity, and the mother working in “education, training, and library” occupations; whereas among unmarried women without a father acknowledged on their child's birth certificate, all our findings are muted. A summer first birth does not depend on socioeconomic characteristics, although it is the most common birth season in the USA. Among married women aged 20–45, we estimate the average marginal willingness to pay (WTP) for a spring birth to be 877 USD. This implies a willingness to trade‐off 560 grams of birth weight in the normal range to achieve a spring birth. Finally, we estimate that an increase of 1,000 USD in the predicted marginal WTP for a spring birth is associated with a 15 pp (percentage points) increase in the probability of obtaining an actual spring birth.     

Doubly Robust Estimation of Causal Effects with Multivalued Treatments: An Application to the Returns to Schooling

This paper provides doubly robust estimators for treatment effect parameters which are defined in a multivalued treatment effect framework. We apply this method to the unique dataset of the 1970 British Cohort Study (BCS70) to estimate returns to various levels of schooling. The analysis is carried out for female and male samples separately to capture possible gender differences. Average returns are estimated for the entire population, as well as conditional on having a specific educational achievement. For males, relative to no qualification, we find an average return to O‐levels of 6.3%, to A‐levels of 7.9% and to higher education of 25.4%. The estimated average returns to O‐level and A‐level relative to no qualification are insignificant for females, whereas the return to higher education is 19.9%.Copyright © 2014 John Wiley & Sons, Ltd.     

Intrapreneurship in the Spanish context: a regional analysis

The objective of this article is to examine the influence of internal and external (environmental) factors on intrapreneurship in the Spanish context, considering differences among regions. Methodologically, the study applies logistic regression and uses data from the Spanish Global Entrepreneurship Monitor for the year 2011. The main findings of the research show through a double conceptual framework (resource-based theory and institutional economics) the direct effect of both internal factors – opportunity recognition and social capital – and environmental factors – fear of failure and education – on intrapreneurship. In addition, the role of fear of failure is reinforced as it has the indirect (moderating) effect; this effect is particularly relevant in lower income regions. The study contributes both theoretically (developing literature and provoking discussion in the field of intrapreneurship) and empirically (providing useful insights for the design of governmental policies for fostering entrepreneurial activities within firms).     

Does Home Ownership by Parents Have an Economic Impact on Their Children?

This paper uses the Panel Study of Income Dynamics to explore the impact of housing on children's productivity through educational attainment and through their housing choices as adults after they leave their parent's home. After controlling for other factors that are normally hypothesized to affect an individual's education and earnings, we find that the average child of homeowners is significantly more likely to achieve a higher level of education and, thereby, a higher level of earnings. We also find that having controlled for the factors traditionally thought to influence an individual's choice of housing tenure, as well as other parental characteristics, the housing tenure of parents plays a primary role in determining whether or not the child becomes a homeowner.     

高职数控技术专业技能实训教育教学方法研究

高职教育实行工学相结合的方式即:在"做中学"、学中做"的过程中培养高技能人才。高职院校的技能实训课程是体现其工学相结合办学特色的关键所在,因此有效提升高职院校技能实训效果、改革教育教学思想就显得尤为重要。     

口腔医学技术专业实习鉴定手册的设计与应用

目的:探讨实习鉴定手册在口腔医学技术专业实习教学中的应用效果。方法:将36名学生随机分成两组,实验组采用新的实习鉴定手册,对照组采用旧的实习鉴定手册,比较两组学生技能考核成绩并评价其效果。结果:实验组学生的考核平均成绩较对照组高(P<0.05)。学生对新的实习鉴定手册的评价好。结论:实习鉴定手册能为实习工作提供指导,能客观反映学生实习情况,评价实习质量。