Dipartimento di Statistica "Giuseppe Parenti"
Seminari - Abstract
a.a. 2009-2010

Abstract 2009-2010


The transition out of the parental home among second generation migrants in Spain: A cross-classified Multilevel Analysis

Bruno Arpino (Università Bocconi)

This paper presents a model for the analysis of parental home leaving determinants for second generation migrants in Spain by simultaneously taking into account their place of origin and the province of residence. Using a cross-classified multilevel analysis it is shown that variation across origin groups is much larger than that due to province of residence. However, variance at the province level is not negligible. It is also found that migrants are extremely heterogeneous with respect to their origin but geographical clustering is evident. Finally, we find that almost all migrants groups show higher probability of leaving home than natives. We also plan to use multiple membership models to keep into account the effect of previous province of residence.

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An M-quantile Random Effects Model for Hierarchical and Repeated Measures Data

Nicola Salvati (Università di Pisa)

Quantile analysis of hierarchical and repeated measures data has recently attracted some interest. The most recent attempt for extending the quantile regression model into a random effects quantile model is described in Geraci and Bottai (2007). In this work we propose an alternative approach for accounting for the hierarchical structure of data when modelling the quantiles of f (y |X). In particular, we extend the M-quantile model into an M-quantile random effects model. The proposed model allows for outlier robust estimation of both Þxed and random effects. In addition, by modelling M-quantiles, instead of the ordinary quantiles, we gain algorithmic stability.

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Marginal Effect Using The Conditional Distribution Dynamics Approach

Angela Parenti (Università di Pisa)

The paper describes a two-stage procedure for estimating the conditional distribution dynamics. The proposedmethodology is evaluated by a Monte Carlo study on the growth of income across a large sample of countries. The first stage consists in the estimate of the growth regression by parametric and/or semiparametric methods; the estimate is then used to calculate the counterfactual distribution and the marginal impact related to a specific explanatory variable. In the second stage the impact on the distribution dynamics of the selected variable is analyzed by estimating the counterfactual stochastic kernel and the conditional distribution of marginal impact. The methodology also provides a diagnostics for detecting potential distribution effect of omitted variables in the growth regression.

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Valutazione di sistemi probabilistici di identificazione indiretta basati su evidenze di DNA nucleare

Fabio Corradi (Università di Firenze)

La possibilità di riuscita di una identificazione indiretta basata su loci STR vari in funzione di molti fattori, fra i quali la distanza nel pedigree familiare fra le persone che richiedono l'identificazione e il membro cercato, nonchè le frequenze alleliche corrispondenti ai genotipi delle persone che nella famiglia provvedono evidenza genetica. Nonostante sia opinione comune che ci possa essere molta variabilità fra caso e caso, la valutazione identificativa viene generalmente eseguita facendo uso di un numero e qualità di loci dipendente dalla disponibilità e dalla convenienza economica di kit largamente diffusi sul mercato. Lo scopo di questo lavoro è quello di proporre una valutazione probabilistica ex-ante di una richiesta di identificazione facendo uso dei dati genici dei familiari misurati rispetto ad un kit scelto dall'utilizzatore. Sulla base dei risultati risulterà possibile dare un giudizio sull'opportunità di procedere alla stessa acquisendo le evidenze genetiche del candidato all'identificazione oppure se riproporre la questione identificativa facendo uso di evidenze differernti.

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Propensity score reweighting in analysis of the gender pay gap

Philippe Van Kerm (CEPS/INSTEAD)

This paper revisits estimation of Oaxaca – Blinder decomposition of wage differentials using weighted least squares in order to achieve greater robustness against model misspecification when the distribution of covariates are highly imbalanced across the groups compared. Monte Carlo simulations and an empirical application to gender wage differentials on the Socio – Economic Panel „LIEWEN ZU LËTZEBUERG‟ (PSELL) show how WLS estimates are a much more accurate estimate of the wage differentials than OLS ones.

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L'indagine sui bilanci delle famiglie italiane

Andrea Neri (Banca d'Italia)

Disporre di informazioni sul tenore di vita delle famiglie e sui loro comportamenti economici e finanziari è cruciale, sia perché si tratta di temi assai rilevanti nel dibattito politico ed economico-sociale, sia perché costituisce la base essenziale per impostare azioni di policy e verificarne nel tempo l'efficacia. La Banca d'Italia conduce da oltre 40 anni un'indagine sui redditi e la ricchezza delle famiglie italiane, diffondendone i principali risultati e mettendone a disposizione per finalità di ricerca i microdati. Il seminario si propone di descrivere le principali caratteristiche e modalità di utilizzo di tale indagine. Verranno inoltre discusse le principali complicazioni legate all'uso di un'indagine complessa a fini di ricerca.

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Semiparametric methods for causal inference: the effect of debit cards on household spending

Andrea Mercatanti

Motivated by recent findings in the field of consumer science, this paper proposes an application of power series methods in order to evaluate the effect of debit cards (i.e. Bancomat) on household consumption. The basic assumption is unconfoundedness and it requires the adoption of debit cards is independent on the potential consumptions given a set of pre-treatment variables. This offers the advantage of avoiding the introduction of assumptions regarding the link between observable and unobservable quantities, and it also improves the precision relative to other main methodological options. The analysis results in positive effects on household monthly spending.

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Estimating finite mixture models: theoretical and computational issues

Paolo Frumento (Università di Pisa)

We investigate the likelihood surface of finite mixture models; stationary points are classified into three main categories, i.e., local maxima, spurious maxima, and saddle points. Due to their presence, in some settings, obtaining a reliable maximum likelihood estimates (MLE) is a difficult task. We exploit a genetic algorithm for the search of the true MLE; a flexible software is developed and presented and some simulation results are discussed.

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Healthcare utilization, socioeconomic factors and child health in India

Alok Bhargava (University of Houston)

This paper modelled the proximate determinants of height, weight and hemoglobin concentration of over 25,000 Indian children using data from the National Family Health Survey-3. The effects of healthcare services utilization, food consumption patterns and maternal health status on child health were investigated in a multidisciplinary framework. The results from models for birth weight and size showed that antenatal care, birth intervals, and maternal education, food consumption patterns and nutritional status were significant predictors. Second, models for children’s heights and weight showed beneficial effects of child vaccinations against DPT, polio, and measles, and negative effects of not utilizing government health facilities. Methodological issues such as potential endogeneity of birth variables and appropriateness of combining height and weight as the Body Mass Index were tackled. Third, models for children’s hemoglobin concentration indicated beneficial effects of food consumption patterns, treatment against intestinal parasites and maternal BMI. Finally, models were estimated for maternal weight and hemoglobin concentration. Overall, the results provide policy insights for improving maternal and child health in India.

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Demographic Effects on GDP per Capita: A Cross-National Study

Peter McDonald (Australian Demographic and Social Research Institute and President of IUSSP)

In the context of low fertility, there is a concern about future decline in the size of the labour force and its potential economic impacts. This can be addressed through increases in fertility but attention has also been addressed by demographers towards ‘replacement migration’ – using migration to make up for the deficit in labour supply. Recently demographers have been asking questions like: what level of migration would it take to maintain a constant number of people at age 30 in the future? Why should the aim be to have a constant number of people at age 30? This seems to be an unsophisticated approach? It is not difficult to construct models that provide much more useful results for alternative demographic futures than mere replacement of the population at age 30.Much more meaningfully, we can model future labour supply or future GDP or future GDP per capita. This paper uses the computer software, MoDEM2, to model these more useful outcomes under varying scenarios for seven countries: Italy, Spain, Germany, Austria, France, Sweden and Japan. The results show that many countries facing rapid ageing of their populations could alleviate the impact on GDP per capita by increasing participation and, ideally, increasing their low rates of labour productivity. For other countries where participation is already relatively high, dem0ographic approaches (higher fertility or higher migration) would be required but these impacts are slow. Almost all countries face a major fall in rates of growth of GDP per capita in the next decade as a result of the retirement from the labour force of the baby-boom generation.

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Theoretical Foundations for the Analysis of Fertility: Gender Equity

Peter McDonald (Australian Demographic and Social Research Institute and President of IUSSP)

In 2000, I published the following: "Very low fertility as observed in many advanced countries today is the result of incoherence in the levels of gender equity inherent in social and economic institutions. Institutions which deal with women as individuals are more advanced in terms of gender equity than institutions which deal with women as mothers or members of families. There has been considerable advance in gender equity in the institutions of education and market employment. On the other hand, the male breadwinner model often remains paramount in the family itself, in services provision, in tax-transfer systems and in industrial relations. This leaves women with stark choices between children and employment, which, in turn, leads to some women having fewer children than they would like to have, and very low fertility." In this paper, I revisit this work to provide further specification of the theory. In this paper I argue that low fertility is the result of reactions of some women to perceived inequity in the social and economic context in which they live. Not being able to have a political impact to change work and family policy, women react by not having children. This is a manifestation of Nancy Fraser’s concept of parity of participation. I argue the theory can only be tested across social contexts or across time. I provide directions for how the theory might be tested.

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International Migration and Demography: a Two-Way Interaction

Philippe Fargues (European University Institute)

Are there links between the demographic transition and international migration, i.e. between one of the most massive changes to affect humanity in modern times and one of the most significant dimensions of connectivity between peoples? While many empirical studies have highlighted the reciprocal implications between demographic growth and migration, theory is rather silent: international migration theory does not put much emphasis on demography and demographic theory simply ignores international migration. While the model of demographic transition postulates a functional link between birth and death rates, there is no equivalent, cohesive model that would posit a relationship between migration, fertility and mortality. The presentation explores whether demographic change and migration can be intrinsically linked. It deals with only one facet of the demographic transition, which is the shift from high to low birth rates and its sociological correlate, the gradual substitution of a dominant pattern of large families with one of small ones. The other facet, which is the decline of mortality, the increase in longevity and the subsequent changes in the generational composition of the family, will not be tackled here, even though one may assume that this facet is also linked with migration. Part I, based on published works by Fargues (2006), focuses on the impact of international migration on the demographic transition and, more precisely, on birth control and the transition from high to low fertility rates amongst migrants in host countries and non-migrants in source countries. It argues that, because migrants remit ideas to their home countries and because most recent migration has been from high to low birth-rate countries, international migration has contributed to spreading values and practices that produce low birth rates in origin countries. International migration has, therefore, led to a smaller world population than the one that would have been observed in a zero migration scenario. Part II is entirely new and tackles the symmetrical influence of demographic change on international migration. It shows that declining birth rates in origin countries generate a new profile of the migrant. While migrants of earlier times had started to build a family before migrating, new migrants typically leave no wives or children in the home country, as a result of relatively unchanged age patterns of migration while marriage takes place later in the life cycle and fewer children are procreated. The conclusion suggests that this fundamental change may produce a critical shift in the economy of migration. Until recently migrants from the developing world were motivated by an altruistic drive to feed and educate their families at home. Remittances were the main, if not the only, reason for emigration. Today, young migrants’ goal is more likely to be self-accomplishment. Unlike their predecessors, the primary objective of typical migrants is no longer to improve the family’s standing at home for the mere reason that there is no longer such a family, but to increase opportunities for themselves. Remittances shift from an altruistic to a selfish use and migrants have an increasing propensity to accumulate not only financial capital, but also individual human capital through education and experience.

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Ultimo aggiornamento 25 ottobre 2010.