Η αύξηση των ποσοστών της παχυσαρκίας, σε παγκόσμιο επίπεδο, ακολουθεί αυξανόμενους ρυθμούς κατά τη διάρκεια των τελευταίων δεκαετιών, συγκεντρώνοντας το ενδιαφέρον ενός σημαντικού αριθμού επιστημόνων στον τομέα των οικονομικών της υγείας. Η παρούσα διατριβή έχει σκοπό να καλύψει τέσσερα ερευνητικά ερωτήματα που σχετίζονται με τα οικονομικά της παχυσαρκίας. Συγκεκριμένα, στα πλαίσια του πρώτου δοκιμίου, η παχυσαρκία μοντελοποιείται ως μια στοχαστική διαδικασία, διερευνάται ο δυναμικός της χαρακτήρας καθώς και οι πηγές της παρατηρούμενης εμμονής. Για αυτό το σκοπό εκτιμώνται κατάλληλα δυναμικά υποδείγματα διακριτών επιλογών, χρησιμοποιώντας διαστρωματικά στοιχεία χρονολογικών σειρών για την περίπτωση ενηλίκων στις ΗΠΑ (NLSY79). Στα πλαίσια του ίδιου κεφαλαίου, επιχειρείται επίσης και μια μελέτη της εμμονής στο σύνολο των κατηγοριών του σωματικού βάρους (φυσιολογικού βάρους, υπέρβαροι, παχύσαρκοι) εφαρμόζοντας δυναμικά διατεταγμένα υποδείγματα. Τέλος, παρουσιάζονται οι απορρέουσες προτάσεις πολιτικής. Στη συνέχεια, χρησιμοποιώντας διαχρονικά στοιχεία από την ίδια βάση δεδομένων (NLSY79), διερευνάται η εμμένουσα συμπεριφορά της διάρκειας της παχυσαρκίας καθώς και οι προσδιοριστικοί παράγοντες των πιθανοτήτων εξόδου από την παχυσαρκία και επαν-εισόδου στην παχυσαρκία. Εφαρμόζοντας μη-παραμετρικά μοντέλα καθώς και πολυ-μεταβλητά διακριτά υποδείγματα κινδύνου, που λαμβάνουν υπόψη τους τη μη-παρατηρούμενη χρονικά αμετάβλητη ετερογένεια των ατόμων, καταδεικνύεται ότι η πιθανότητα εξόδου από την κατάσταση της παχυσαρκίας χαρακτηρίζεται από μια αρνητική εξάρτηση από τη διάρκεια (negative duration dependence). Όσον αφορά στις επιπτώσεις πολιτικής, η ύπαρξη «πραγματικής» εξάρτησης από τη διάρκεια υποδηλώνει ότι οι παρεμβάσεις των πολιτικών δημόσιας υγείας πρέπει να στοχεύουν πρωτίστως στους «πρόσφατα παχύσαρκους». Το τρίτο εμπειρικό δοκίμιο πραγματεύεται τις επιπτώσεις της παχυσαρκίας στην αγορά εργασίας των ΗΠΑ και ειδικότερα στην περίπτωση των μισθών. Εκμεταλλευόμενοι τα ευρήματα των προηγούμενων αναλύσεων σχετικά με την εμμένουσα συμπεριφορά της παχυσαρκίας, μπορεί να θεωρηθεί ότι η παχυσαρκία αποτελεί μια σχετικά σταθερή κατάσταση που χαρακτηρίζεται από μειωμένη κινητικότητα. Ως εκ τούτου, γίνεται εφικτή η ανάλυση των μισθολογικών χασμάτων μεταξύ παχύσαρκων και μη-παχύσαρκων εργαζομένων, εφαρμόζοντας κατάλληλα υποδείγματα διάσπασης μισθών κατά Oaxaca-Blinder. Τα σχετικά ευρήματα καταδεικνύουν την ύπαρξη μισθολογικών χασμάτων εις βάρος των παχύσαρκων λευκών ανδρών και γυναικών. Τα εν λόγω μισθολογικά χάσματα μπορούν να ερμηνευθούν -σε ικανοποιητικό βαθμό- από τις διαφορές στα παρατηρούμενα χαρακτηριστικά μεταξύ παχύσαρκων και μη παχύσαρκων εργαζομένων και, ειδικότερα, από τις διαφορές στο επίπεδο εκπαίδευσης. Τέλος, το τελευταίο δοκίμιο της παρούσας διατριβής διερευνά τους προσδιοριστικούς παράγοντες των αποτελεσμάτων σωματικού βάρους στην περίπτωση της Ελλάδας χρησιμοποιώντας -για πρώτη φορά- πρόσφατα δεδομένα από την Εθνική Έρευνα Υγείας (GNHS-2009). Για τις ανάγκες της ανάλυσης εφαρμόστηκε μια σειρά από οικονομετρικές τεχνικές εκτίμησης διαφορετικής φύσης (γραμμικά υποδείγματα ελαχίστων τετραγώνων, διατεταγμένα μοντέλα και μη-δεσμευμένες παλινδρομήσεις ποσοστιαίων σημείων). Τα σχετικά αποτελέσματα δείχνουν ότι οι εκτιμήσεις μη-δεσμευμένων παλινδρομήσεων ποσοστιαίων σημείων οδηγούν σε σημαντικές ποσοτικές και ποιοτικές διαφοροποιήσεις στις επιπτώσεις των διαφόρων προσδιοριστικών παραγόντων του σωματικού βάρους, σε σχέση τόσο με τα διατεταγμένα μοντέλα όσο και με τις γραμμικές παλινδρομήσεις ελαχίστων τετραγώνων. Επομένως, οι υπεύθυνοι χάραξης πολιτικής για την αντιμετώπιση του αυξημένου σωματικού βάρους στην Ελλάδα θα πρέπει να βασίζονται σε εμπειρικά μοντέλα και τεχνικές εκτίμησης που λαμβάνουν υπόψη τους το σύνολο της κατανομής του ΔΜΣ και όχι συγκεκριμένα τμήματά της. / Recently economists pay a lot of attention on the analysis of obesity since the prevalence of obesity is widespread. This dissertation examines four research questions associated with the Economics of Obesity. Specifically, with respect to the first empirical chapter, obesity is modeled as a dynamic stochastic process and patterns of obesity experiences are investigated. Longitudinal data from US adults (NLSY79) and appropriate dynamic models were utilized. Strong persistence was detected in obesity and the body-mass-index (BMI), albeit with different properties. While controlling for initial conditions (early-life endowments and family background), the identified obesity persistence was decomposed into unobserved heterogeneity and genuine state dependence. Results from the sensitivity analysis show that obesity has a lasting effect, which however is not stable across the BMI distribution, exhibiting a steeper decline at BMI levels close to the clinical definition of obesity. Moreover, in the same chapter, we also explore the dynamic behavior of alternative fatness states (normal weight, overweight and obese) and the corresponding persistence, utilizing appropriated dynamic ordered models. Relevant policy implications are discussed. The second chapter investigates the dynamic patterns the duration of obesity and identifies the determinants of obesity-spell exits and re-entries. We utilize longitudinal data from the NLSY79, as before. Non-parametric techniques are applied to investigate the relationship between exit from obesity and spell duration. Multivariate discrete hazard models are also estimated, taking into account duration dependence and observed and time-invariant unobserved heterogeneity. In all cases, the probability of exiting obesity is inversely related to the duration of the obesity spell. Without controlling for unobserved heterogeneity, the probability of exit after one wave in obesity is 31.5 per cent; it is reduced to 3.8 per cent after seven or more waves. When time-invariant unobserved heterogeneity is taken into account, the estimated probabilities are slightly larger and broadly similar (36.8 and 10.3, respectively), which suggests that the identified negative duration dependence is not primarily due to composition effects. The obtained results indicate that public health interventions targeting the newly obese may be particularly effective at reducing incidence of long durations of obesity. In the third empirical chapter we investigate obese/non-obese wage differentials using data for white individuals from the 2000 wave of the NLSY79. Based on the results from the previous chapters, we assume that obesity is a rather permanent characteristic that associated with relatively small mobility. Hence, typical Oaxaca-Blinder wage decompositions could be applied in order to identify the proportion of the observed gender-specific wage differential between obese and non-obese. Based on numerous specifications and alternative sub-samples the results provide strong evidence for the existence of wage differentials in favor of non-obese individuals, which can be mostly explained by differences in early human capital investments and especially schooling investments. Finally, an attempt was made to identify the determinants of body-weight in Greece, utilizing individual-level data from the National Health Survey of 2009. BMI is treated as both, a cardinal and an ordinal measure of body-weight, while different estimation techniques are applied (OLS, ordered probit and unconditional quantile regressions). We employ a wide range of demographic, socio-economic, lifestyle, health-related and regional characteristics. The unconditional quantile regression estimates indicate that the impact of several correlates across the BMI distribution is distinctive. This differentiation concerns the effects of age, education, family income, physical activity, employment status, smoking, health-related impairments and regional characteristics. Thus, examining the entire BMI distribution and targeting specific segments of the Greek population can improve the efficiency of public health policies against obesity.

This dissertation consists of three essays in applied microeconomics. These essays investigate different aspects of the impact of technology on labor market outcomes and firm strategy. The first essay, co-authored with Ronald L. Oaxaca, is in the area of labor economics and it investigates the relation between non-neutral technological change and the gender gap in wages. This essay is the first to address the issue of the recent narrowing of the gender wage gap in the context of technological change by using a novel approach to separately estimate the effects of technological change and discrimination on the gender wage gap. Using a constant elasticity of substitution production function and Current Population Survey data on employment and wages by industry and occupation, the results show that changes in non-neutral technological change explain between 5% and 9% of the narrowing of the wage gap between 1979 and 2001. The latter two essays span topics across applied industrial organization, firm strategy and labor economics. The second component of my dissertation investigates the relation between technological knowledge diffusion through the labor mobility of scientists and the organization of R&D activities by innovative firms. Using a labor mobility measure from the Current Population Survey March Supplements as a measure for inter-firm technology spillovers and a panel of R&D alliance data for 18 U.S. industries between 1989 and 1999, a Poisson estimation shows that firms facing a 10% increase in the labor mobility of scientists have a 5% increase in the annual number of R&D collaborations. The third essay is an empirical analysis of the impact of knowledge dissemination generated by the labor mobility of scientists and engineers on a measure of the pace of innovation. Using an unbalanced panel of firms containing patent data matched with firm data across eight innovative industries, from 1989 to 1998, along with a measure of the labor mobility of scientists and engineers, this essay provides evidence that firms in industries exposed to levels of labor mobility of scientists and engineers that differ by 1%, have an expected time lag between sequential generations of technologies that differs by 0.56 years.

This paper analyzes the Swedish labor market during the interwar and early postwar period within the framework of modern labor market theory. The development of unemployment during this period - according to the commonly cited source of labor union reports - represents a conundrum for research. The unemployment rate rose after the initial diverse shock of 1921 and stayed at a permanently higher level for the rest of the interwar period. This development was reversed after World War Two when the unemployment rate decreased and stayed permanently low for the rest of the postwar period until the oil price chock of the 1970s. In a first step the available sources of unemployment statistics is investigated and compared. The general conclusion is that the labor union reports overestimate the level of economy wide unemployment while being a reasonably good indicator of movements in the rate. While no assertion of absolute levels can be made the conclusion might be drawn that the equilibrium level of unemployment decreased from a higher interwar level down to a substantially lower postwar one. The paper then turns to the overarching question of the possible mainsprings of this development. The concept of the warranted wage - defined as total factor productivity growth divided by the labor share - have been used to explained the development of unemployment in the OECD from the 1970s. The theory pertains that movements in the bargained wage above or below the warranted wage will render movements in the equilibrium unemployment rate. This theoretical framework is used to analyze the Swedish inter- and early postwar experience. The warranted wage in the manufacturing sector and the whole economy is respectively estimated using historical national accounts and growth accounting. The development is then compared to the progress of real labor costs. The conclusion is that the 1920s experienced a negative growth in the warranted wage - and while real labor cost decreased during the period - wages were not cut enough in order to keep profits unchanged for firms. The opposite can be concluded for the succeeding 1930s and 1940s which instead saw a positive evolution of the warranted wage with real labor costs not growing at the same rate. The movements of real labor costs in relation to the warranted wage thus makes this factor a plausible candidate for explaining movements in the unemployment rate during the period understudy.

The three chapters of my dissertation examine immigrant assimilation in the Canadian labour market. Through three levels of analysis, which are distinguished by the sample restrictions that are employed, I investigate immigrant labour force and job dynamics, immigrant propensity for self-employment, and immigrant wage assimilation, respectively. In the first chapter, I exploit recently-introduced immigrant identifiers in the Canadian Labour Force Survey (LFS) and the longitudinal dimension of these data to compare the labor force and job dynamics of Canada's native-born and immigrant populations. I am particularly interested in the role of job, as opposed to worker, heterogeneity in driving immigrant wage disparities and in how the paths into and out of jobs of varying quality compares between immigrants and the native-born. The main finding is that the disparity in immigrant job quality, which does not appear to diminish with years since arrival, reflects a combination of relatively low transitions into high-wage jobs and high transitions out of these jobs. The former result appears about equally due to difficulties obtaining high-wage jobs directly out of unemployment and in using low-wage jobs as stepping-stones. I find little or no evidence, however, that immigrant jobseekers face barriers to low-wage jobs. We interpret these findings as emphasizing the empirical importance of the quintessential immigrant anecdote of a low-quality "survival job" becoming a "dead-end job". The second chapter analyzes immigrant choice of self-employment versus paid employment. Using the Canadian Census public use microdata files from 1981 to 2006, I update the Canadian literature on immigrant self-employment by examining changes in the likelihood of self-employment across arrival cohorts of immigrants and how self-employment rates evolve in the years following migration to Canada. This study finds that new immigrants, who arrived between 1996 and 2005, turned to self-employment at a faster rate than the earlier cohorts and that immigrants become increasingly likely to be self-employed as they spend more time in Canada. More important, I examine immigrant earnings outcomes relative to the native-born, instead of within, sectors and thus explore the extent to which a comparative advantage in self-employment, captured by the difference in potential earnings between the self- and paid-employment sectors, can explain the tremendous shift toward self-employment in the immigrant population. The results show that the earnings advantage between the self- and the paid-employment sectors accounts for the higher likelihood of self-employment for traditional immigrants in the years following migration. However, the potential earnings difference cannot explain the reason that non-traditional immigrants are more likely to be self-employed as they consistently lose an earnings advantage in the self-employment sector relative to the paid-employment sector. My paper suggests that immigrants may face barriers to accessing paid-employment, or immigrants are attracted to self-employment by non-monetary benefits. Lastly, in the third chapter, studies which estimate separate returns to foreign and host-country sources of human capital have burgeoned in the immigration literature in recent years. In estimating separate returns, analysts are typically forced to make strong assumptions about the timing and exogeneity of human capital investments. Using a particularly rich longitudinal Canadian data source, I consider to what extent the findings of the Canadian literature may be driven by biases arising from errors in measuring foreign and host-country sources of human capital and the endogeneity of post-migration schooling and work experience. The main finding is that the results of the current literature by and large do not appear to be driven by the assumptions needed to estimate separate returns using the standard data sources available.

Using data from the 2013 American Community Survey, the author examines the wage returns to same-sex parenthood and their role in the sexual orientation wage gap. Specifically, he compares individuals by gender, sexual orientation, and household earner status. The importance of accounting for household specialization among heterosexual men and women is illustrated by the significant differences in returns to parenthood between heterosexuals of the same gender, but different earner statuses. The empirical results show that gay men face a fatherhood penalty for the presence of children between the ages of 5 and 18 irrespective of earner status. Lesbians on the other hand, experience motherhood premiums for the presence of children under the age of 5, but modest motherhood penalties for the presence of children between the ages of 5 and 18. Ultimately, differences in the wage returns to parenthood for gays, lesbians, and their respective heterosexual counterparts play a negligible role in sexual orientation wage differentials.

This paper estimates the effects of imports on employment, wages, and the wage share in Austria for the period of 1990-2005 using panel data of manufacturing industry. Imports are disaggregated according to their origin and as final vs. intermediate imports. There is evidence of significant negative effects of imports on employment, wages and the wage share. Particularly workers in high skilled sectors experience negative effects. Offshoring to both Eastern Europe and the developed countries have a negative impact on employment, whereas offshoring to the East has a positive effect on wages, indicating the dominance of scope effects. (author´s abstract) / Series: Department of Economics Working Paper Series

Economides (1986) has shown that within a linear city an equilibrium exists in a two-stage location-price game when the curvature of the transportation cost function is sufficiently high. One important point is that not all of these equilibria are at maximal differentiation. In this paper we include an additional stage with decentralized wage bargaining. This intensifies price competition resulting in locations that are nearer to the extremes of the city. The magnitude of this effect depends on the bargaining power of the unions. (author's abstract) / Series: Department of Economics Working Paper Series

This dissertation examines the effects of career interruptions on workers’ wages. In chapter four I examine whether controlling for the type of interruption differently affects men’s and women’s wages and therefore can be used to explain the remaining gender wage differences. The increased participation of married women in the labor force has increased their wages from just 30% of men’s wages in 1890 to nearly 80% as of 2001. Thus, although the gender wage gap has narrowed over time, it has yet to be eliminated. One argument for the persistence of the gender wage gap is that previously researchers have used poor measures of experience to estimate men’s and women’s wages. Although previous studies have made strides in measuring experience, including controls for the timing of work experience, the gender wage gap persists. I extend the wage-gap literature by including controls for the types of interruptions men and women encounter. Because they typically experience different types of interruptions, I examine whether the varying types affect wages differently. I control for the types of interruptions and find similar effects for men’s and women’s wages. My study shows that types of job interruptions do not explain the remaining wage differentials. The fifth chapter extends from the fourth chapter by including controls for all periods of unpaid leave from work. I examine whether wage differences exist between workers who return to their current employer post-interruption versus those who change employers post-interruption. I find differences in the wage effects from different types of unpaid leave for men and women. Chapter six extends from previous chapters by including controls for all periods of paid leave from work in addition to unpaid leaves from work. I examine whether depreciation effects occur when women spend time out of work but receive compensation through paid maternity leaves. I find no evidence that time out of work because of paid maternity leaves depreciates skills.

Prior research from the U.S. and abroad reveals a sizable lesbian earnings advantage over otherwise-similar heterosexual women. Using data from the 2000 U.S. Census and 2005-2010 American Community Surveys, we estimate traditional earnings equations and find robust evidence of a lesbian premium, corroborating the findings of previous studies. Using within-sample maternity incidence as an estimate of employers' forward-looking expectations, we then examine whether differences in the perceived likelihood of an employee requiring maternity leave, here-labelled 'maternity risk', contribute to the lesbian pay gap. Results from a direct assessment suggest that maternity risk adversely affects income, and that accounting for near-term differences in maternity risk reduces the lesbian premium by approximately ten to fifteen percent. Further analyses, using proxy variables for differential maternity risk, yield similar results. As such, the persistent finding of a lesbian earnings advantage in previous studies can be attributed, at least in part, to employers' aversion to maternity risk and its associated costs. These findings are also of critical importance to the general labour-market discrimination literature. Given the adverse earnings effect of maternity risk, our analysis suggests that estimates of the well-established gender earnings disparity are likely to be considerably smaller when incorporating maternity risk into the analysis. Absent the ability to adequately control for maternity risk, strict attention should be paid to potential upward bias in estimated earnings differentials. Moreover, policymakers should consider the broader implications of maternity-leave policy on the labour-market outcomes of females. In this respect, maternity-leave policy may influence the hiring and promotion decisions of employers, thereby indirectly affecting sexual-orientation and gender equality in the labour market. However, further research in this area is still required, given the limitations inherent in the direct and indirect analyses.

La informalidad laboral y la pobreza tienen altos niveles de incidencia en América Latina. Lo anterior se explica porque en países de ingreso medio y bajo como los latinoamericanos, el vínculo entre la pobreza y el mercado laboral no se presenta a través de la problemática del desempleo, sino principalmente por la situación en el empleo. El objetivo de la tesis es explorar el vínculo entre informalidad laboral y pobreza en Colombia. Para ello, a través de diferentes metodologías, se estimarán las diferencias en remuneración asociadas a informalidad, y luego con ejercicios de microsimulación se estima el potencial efecto de la formalización sobre la pobreza, así como la influencia que ha tenido la informalidad sobre la reducción de la pobreza presentada entre 2002 y 2013 en Colombia. Se encuentra que los informales tienen remuneraciones inferiores entre 37 y 44% respecto a los formales, la eliminación de esas brechas reduciría la pobreza entre 40 y 44%, sin embargo, la informalidad ha tenido poca influencia en la reducción efectiva de la pobreza en el periodo analizado. / Labor informality and poverty have high levels in Latin America. The link between poverty and labor market in developing countries is not through unemployment but with employment situation. The purpose of this thesis is to analysis the hookup between labor informality and poverty in Colombia. In order to do that, wage differentials by informality are estimated, afterwards the effect of formalization on poverty will be calculated, as well as the influence of changes in labor informality on Colombia’s poverty reduction from 2002 until 2013. It is found that wage differentials between formal and informal workers are from 37 to 44%, and if informality was eliminated, poverty would go down from 40 to 44%. However, informality has had low influence in Colombia’s poverty reduction in last decade.