Professor Matthias Parey

We measure selection among high-skilled emigrants from Germany using predicted earnings. Migrants to less equal countries are positively selected relative to nonmigrants, while migrants to more equal countries are negatively selected, consistent with the prediction in Borjas (1987). Positive selection to less equal countries reflects university quality and grades, and negative selection to more equal countries reflects university subject and gender. Migrants to the United States are highly positively selected and concentrated in STEM fields. Our results highlight the relevance of the Borjas model for high-skilled individuals when credit constraints and other migration barriers are unlikely to be binding.

We investigate the e¤ect of studying abroad on international labor market mobility later in life for German university graduates. As a source of identifying variation, we exploit the introduction and expansion of the ERASMUS student exchange program, which significantly increases a student's probability of studying abroad. Using an Instrument Variable approach we control for unobserved heterogeneity between individuals who studied abroad and those who did not. Our results indicate that student exchange mobility is an important determinant of later international labor market mobility: We find that studying abroad increases an individual's probability of working in a foreign country by about 15 to 20 percentage points, suggesting that study abroad spells are an mportant channel to later outmigration. The results are robust to a number of specification checks.

Berkson errors are commonplace in empirical microeconomics. In consumer demand this form of measurement error occurs when the price an individual pays is measured by the (weighted) average price paid by individuals in a specified group (e.g., a county), rather than the true transaction price. We show the importance of such measurement errors for the estimation of demand in a setting with nonsep-arable unobserved heterogeneity. We develop a consistent estimator using external information on the true distribution of prices. Examining the demand for gasoline in the U.S., we document substantial within-market price variability, and show that there are significant spatial differences in the magnitude of Berkson errors across regions of the U.S. Accounting for Berkson errors is found to be quantitatively important for estimating price effects and for welfare calculations. Imposing the Slutsky shape constraint greatly reduces the sensitivity to Berkson errors.

Berkson errors are commonplace in empirical microeconomics and occur whenever we observe an average in a specified group rather than the true individual value. In consumer demand this form of measurement error is present because the price an individual pays is often measured by the average price paid by individuals in a specified group (e.g., a county). We show the importance of such measurement errors for the estimation of demand in a setting with nonseparable unobserved heterogeneity. We develop a consistent estimator using external information on the true distribution of prices. Examining the demand for gasoline in the U.S., accounting for Berkson errors is found to be quantitatively important for estimating price effects and for welfare calculations. Imposing the Slutsky shape constraint greatly reduces the sensitivity to Berkson errors.

We investigate the effect of studying abroad on international labour market mobility later in life for university graduates. We exploit the introduction and expansion of the European ERASMUS student exchange programme as an instrument for studying abroad. We find that studying abroad increases an individual's probability of working in a foreign country by about 15 percentage points. We investigate heterogeneity in returns according to parental education and the student's financial situation. Furthermore, we suggest mechanisms through which the effect of studying abroad may operate.

This paper develops a new method for estimating a demand function and the welfare consequences of price changes. The method is applied to gasoline demand in the United States and is applicable to other goods. The method uses shape restrictions derived from economic theory to improve the precision of a nonparametric estimate of the demand function. Using data from the U. S. National Household Travel Survey, we show that the restrictions are consistent with the data on gasoline demand and remove the anomalous behavior of a standard nonparametric estimator. Our approach provides new insights about the price responsiveness of gasoline demand and the way responses vary across the income distribution. We find that price responses vary non-monotonically with income. In particular, we find that low-and high-income consumers are less responsive to changes in gasoline prices than are middle-income consumers. We find similar results using comparable data from Canada.

This entry discusses programs that support, encourage or administer International Student Mobility (ISM). According to the definition from the Higher Education Funding Council for England (HEFCE, 2004), ISM is “any form of international mobility which takes place within a student’s programme of study in higher education”. ISM programs can refer to supporting outbound students (outward mobility) as well as incoming students from abroad (inward mobility). Students planning a spell abroad can either plan and organize their stay independently (as what are called free movers) or via a student exchange program. This entry begins by providing an overview of patterns of student mobility, and then describes the role of student mobility programs. ISM includes both short-term study abroad visits as well as long-term study abroad stays for entire degree programs. This entry emphasizes study abroad as a part of a student’s higher education studies (often referred to as credit mobility), rather than completing an entire degree program abroad (degree mobility). In the following, the challenges of evaluating the effect of study abroad programs on subsequent outcomes are discussed. The introduction of the ERASMUS program is considered in light of research that has been undertaken using the launch and growth of the program as opportunities to examine and understand the effects of study abroad participation. The entry discusses the role of student exchanges on subsequent international mobility choices, as well as on subsequent labor market outcomes. It concludes by addressing some key open questions in this area.

Quantifying the market size for cannabis is important given vigorous policy debates about how to intervene in this market. We develop a new approach to measuring the size of the cannabis market using forensic economics. The key insight is that cannabis consumption often requires the use of complementary legal inputs: roll-your-own tobacco and rolling papers. The forensic approach specifies how legal and illegal inputs are combined in the production of hand-rolled cigarettes and cannabis joints. These input relationships, along with market adding-up conditions, can be used to infer the size of the cannabis market. We provide proof-of-concept that this approach can be readily calibrated using: (i) point-of-sale data on legal inputs of roll-your-own tobacco and rolling papers; (ii) input parameter estimates drawn from a wide-ranging interdisciplinary evidence base. We implement the approach using data from 2008-9. For those years, the forensic estimates for the UK cannabis market are near double those derived from standard demand-side approaches. We make precise what drives the measurement gap between methods by establishing the adjustments needed to match estimates from alternative approaches. Our analysis develops an agenda on measurement and data collection that allows for credible cost-benefit analysis of policy interventions in illicit drug markets.

We use large-scale panel data from linked decadal censuses in England and Wales to study the responses of both individuals and their partners to rising Chinese import competition in the 2000s. We test whether partners provide insurance against lost household earnings by increasing labour supply. We find that both own and partner responses to the shock vary significantly by gender. Men in households exposed to import competition respond by increasing labour force participation at older ages, and by moving into solo self-employment. This is true both in response to their own trade exposure, and as an 'added worker effect' when their partner is exposed to the shock. By contrast, we find no such response for women, who do not increase labour supply if their male partners were initially employed in exposed industries. In general, self-employment appears to act as an employment buffer for men but not women. The impacts of import competition on partnering and family dissolution also differ according to the gender of those affected: for women below 45, but not men, exposure to the trade shock reduces the likelihood of divorce and of living with a new partner. Overall, our findings underscore the importance of investigating household responses, and the self-employment margin, to fully understand the effects of trade shocks.

We study the intergenerational effects of maternal education on children's cognitive achievement, behavioral problems, grade repetition, and obesity, using matched data from the female participants of the National Longitudinal Survey of Youth 1979 (NLSY79) and their children. We address the endogeneity of maternal schooling by instrumenting it with variation in schooling costs during the mother's adolescence. Our results show substantial intergenerational returns to education. Our data set allows us to study a large array of channels which may transmit the effect of maternal education to the child, including family environment and parental investments at different ages of the child. We discuss policy implications and relate our findings to the literature on intergenerational mobility.

We estimate the effects of in-utero exposure to a trade embargo on survival and human capital in an import-dependent developing country. Using a regression discontinuity design, we find that a nearly comprehensive embargo imposed by India on Nepal in 1989 led to a large decline in reported live births, and increased early life mortality. The decline in births is concentrated in poorer, more remote districts, and is sharper for female births than male births, consistent with documented gender discrimination. Women survivors of exposure are more educated in adulthood than unexposed cohorts.

This paper presents a test for exogeneity of explanatory variables in a nonparametric instrumental variables (IV) model whose structural function is identified through a conditional quantile restriction. Quantile regression models are increasingly important in applied econometrics. As with mean-regression models, an erroneous assumption that the explanatory variables in a quantile regression model are exogenous can lead to highly misleading results. In addition, a test of exogeneity based on an incorrectly specified parametric model can produce misleading results. This paper presents a test of exogeneity that does not assume the structural function belongs to a known finite-dimensional parametric family and does not require estimation of this function. The latter property is important because nonparametric estimates of the structural function are unavoidably imprecise. The test presented here is consistent whenever the structural function differs from the conditional quantile function on a set of non-zero probability. The test has non-trivial power uniformly over a large class of structural functions that differ from the conditional quantile function by O(n−1/2)⁠. The results of Monte Carlo experiments and an empirical application illustrate the performance of the test.