A Machine Learning Approach to Improving Occupational Income Scores

Historical studies of labor markets frequently lack data on individual income. The occupational income score (OCCSCORE) is often used as an alternative measure of labor market outcomes. We consider the consequences of using OCCSCORE when researchers are interested in earnings regressions. We estimate race and gender earnings gaps in modern decennial Censuses as well as the 1915 Iowa State Census. Using OCCSCORE biases results towards zero and can result in estimated gaps of the wrong sign. We use a machine learning approach to construct a new adjusted score based on industry, occupation, and demographics. The new income score provides estimates closer to earnings regressions. Lastly, we consider the consequences for estimates of intergenerational mobility elasticities

Household and Individual Decision-Making Over the Life Cycle: A First Look at Evidence from Peruvian Cohorts

Peruvian society has achieved significant improvements in terms of lower fertility and mortality over the last forty years, which has brought down population growth rates to less than 1. 2% a year. These improvements have led, on average, to a demographic transition with lower dependency ratios. In general, this transition increases the ability of the society to take proper care of its non-working population groups, children and the elderly, which may be reflected in changes in household structure. We identify stylized facts about the implications of these changes at the micro level through the use of pseudo-panels from household-level data for Peru. We calculate age, cohort and year effects for variables related to household structure, educational attainment, labor force participation and savings. We find some evidence that suggests differences, by educational level, in the Peruvian demographic transition. Household size is smaller for the younger cohorts in all households but those with less educated heads. We argue that these different profiles are explained by the fact that reductions in fertility have not reached the less educated. On the one hand, these differences in household size patterns are similar to those in the number of children. On the other hand, cohort patterns in family living arrangements—i. e. , households with extended families—are similar across educational groups. However, family living arrangements change throughout the life cycle, in the sense that extended families are more common for households with very young (under 25) and elderly (over 60) heads. These changes in family arrangements over the life cycle add confusion to the meaning of headship, since in some cases the household reports as its head the older member and in other cases the main income earner. We also find that younger cohorts are more educated, are larger than older ones, and show lower returns to education. This is consistent with an increase in relative supply of educated workers that outpaces the increase in relative demand induced by economic growth, under the assumption of imperfect substitutability between equally educated workers of different cohorts. Finally, we show that intergenerational family arrangements over the life cycle limit the ability of the life cycle hypothesis (LCH) to explain household savings behavior. We find evidence that Peruvian households, especially the less educated, smooth consumption over the life cycle, not only through the typical saving-dissaving mechanism, but also by smoothing income. Net cash transfers, or living arrangements between parents and their offspring, play an important role in this income smoothing.

Gender and Racial Discrimination in Hiring: A Pseudo Audit Study for Three Selected Occupations in Metropolitan Lima

In this paper, we adapt the audit studies methodology to analyze gender and racial differences in hiring for a particular segment of the market of three selected occupations in Metropolitan Lima: salespersons, secretaries and (accounting and administrative) assistants. The adapted pseudo-audit study methodology allow us to reduce the room for existence of statistical discrimination. The results suggest the existence of no significant differences in hiring rates for different gender-race groups but some systematic (and significant) differences in the aimed wages of the individuals in their job search processes.field experiments, discrimination, occupational segregation

The 23 year reminiscence of the SN1987A

Twenty three years ago on February 23, 1987, the explosion of the SN in the L.M.C. was observed both optically and by underground detectors. The optical observations were done in Chile and Australian observatories while the neutrino burst was detected by several underground experiments in the Northern Hemisphere, running at that time: Mt. Blanc in Italy, Kamioka in Japan, and Baksan in Russia and IMB in the USA. For the first time in the history of human existence, an astrophysical phenomenon has been observed in underground detectors. In this astrophysical event, the Mt. Blanc experiment detected five pulses on-line that were not at the same time, as detected by the other three detectors around five hours later. It is still not clear to astrophysicists why two bursts at two different times have been detected and how an SN can generate two neutrino bursts. After 23 years a model has proposed an explanation for a double stage collapse at two different times, as recently suggested by V.S. Imshennik and O. Ryazhskaya. In this paper, a detailed occurrence of something strange that happened on February 23rd is presented while most of the scientific information has been exhibited in other published papers

Tensor envelopes of regular categories

We extend the calculus of relations to embed a regular category A into a family of pseudo-abelian tensor categories T(A,d) depending on a degree function d. Under the condition that all objects of A have only finitely many subobjects, our main results are as follows: 1. Let N be the maximal proper tensor ideal of T(A,d). We show that T(A,d)/N is semisimple provided that A is exact and Mal'cev. Thereby, we produce many new semisimple, hence abelian, tensor categories. 2. Using lattice theory, we give a simple numerical criterion for the vanishing of N. 3. We determine all degree functions for which T(A,d) is Tannakian. As a result, we are able to interpolate the representation categories of many series of profinite groups such as the symmetric groups S_n, the hyperoctahedral groups S_n\semidir Z_2^n, or the general linear groups GL(n,F_q) over a fixed finite field. This paper generalizes work of Deligne, who first constructed the interpolating category for the symmetric groups S_n. It also extends (and provides proofs for) a previous paper math.CT/0605126 on the special case of abelian categories.Comment: v1: 52 pages; v2: 52 pages, proof of Lemma 7.2 fixed, otherwise minor change

Little Higgs models with a light T quark

We study Little Higgs models based on a SU(3)_1 x SU(3)_2 global symmetry and with two scales (the two vacuum expectation values f_{1,2}) substantially different. We show that all the extra vector boson fields present in these models may be much heavier than the vectorlike T quark necessary to cancel top-quark quadratic corrections. In this case the models become an extension of the standard model with a light (500 GeV) T quark and a scalar Higgs field with a large singlet component. We obtain that the Yukawa and the gauge couplings of the Higgs are smaller than in the standard model, a fact that reduces significantly the Higgs production rate through glu-glu and WW fusion. The T-quark decay into Higgs boson becomes then a dominant Higgs production channel in hadron colliders.Comment: 16 pages, version to appear in NP

Essays on Childhood Conditions and Adult Economic and Health Outcomes

This dissertation includes four essays on how childhood interventions affected adult labor market and health disparities. The first chapter investigates how early childhood environment affects longevity by examining the internment of Japanese Americans during World War II as a natural experiment. Using the roster of internees linked to death records in the Social Security Death Index, I find that those who were incarcerated within internment camps during the first four years of life died approximately two years earlier. The effect is larger for those from low socioeconomic status families and those incarcerated in colder climates. I also find that those incarcerated during early childhood were more likely to die of circulatory disease. The second chapter of my dissertation examines how school quality within Japanese American internment camps affected adult educational attainment and labor market outcomes. Using data pooled from the 1980, 1990, and 2000 Censuses, I find that those who were incarcerated during school age were less likely to achieve collegiate or post-collegiate education, and had lower returns to education. The third chapter examines the long-run effects of early-life yellow fever exposure on adult occupational outcomes. Using data from the 100 percent sample of the 1880 Census, I find that those born during yellow fever epidemics were less like to become professionals and more likely to become unskilled laborers. This effect is larger for the children of immigrant mothers, who were more likely to contract yellow fever than natives were. Low birth weight children are earn less and become less educated as adults. The last chapter examines whether the negative effects of low birth weight are mitigated by socioeconomic status. This chapter uses a unique data set of Korean adoptees who were quasi-randomly assigned to families and finds that neighborhood characteristics mitigate the negative effects of low birth weight, whereas family characteristics do not