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Unobserved Heterogeneity (unobserved + heterogeneity)
Selected AbstractsModelling Currency Crises in Emerging Markets: A Dynamic Probit Model with Unobserved Heterogeneity and Autocorrelated Errors,OXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 4 2006Elisabetta Falcetti Abstract The paper investigates the causes of currency crises in emerging markets. We estimate the probability of a currency crisis by applying maximum smoothly simulated likelihood to a dynamic LDV model. This approach allows us to take explicit account of the existence of intertemporal links between crises. The results show that currency crises are influenced by real, monetary, debt and global variables. Past banking crises are significant determinants of the probability of currency crises. Moreover, countries that sharply devalued in the past are less prone to experience another currency crisis. We find evidence of unobserved heterogeneity, which may reflect differences in the countries' institutional/historical background. Finally, the determinants of currency crises differ by type of exchange rate regime. [source] Unobserved Heterogeneity in Models of Competing Mortgage Termination RisksREAL ESTATE ECONOMICS, Issue 2 2006John M. Clapp This article extends unobserved heterogeneity to the multinomial logit (MNL) model framework in the context of mortgages terminated by refinance, move or default. It tests for the importance of unobserved heterogeneity when borrower characteristics such as income, age and credit score are included to capture lender-observed heterogeneity. It does this by comparing the proportional hazard model to MNL with and without mass-point estimates of unobserved heterogeneous groups of borrowers. The mass-point mixed hazard (MMH) model yields larger and more significant coefficients for several important variables in the move model, whereas the MNL model without unobserved heterogeneity performs well with the refinance estimates. The MMH clearly dominates the alternative models in sample and out of sample. However, it is sometimes difficult to obtain convergence for the models estimated jointly with mass points. [source] A Multiple-Record Systems Estimation Method that Takes Observed and Unobserved Heterogeneity into AccountBIOMETRICS, Issue 2 2004Elena Stanghellini Summary. We present a model to estimate the size of an unknown population from a number of lists that applies when the assumptions of (a) homogeneity of capture probabilities of individuals and (b) marginal independence of lists are violated. This situation typically occurs in epidemiological studies, where the heterogeneity of individuals is severe and researchers cannot control the independence between sources of ascertainment. We discuss the situation when categorical covariates are available and the interest is not only in the total undercount, but also in the undercount within each stratum resulting from the cross-classification of the covariates. We also present several techniques for determining confidence intervals of the undercount within each stratum using the profile log likelihood, thereby extending the work of Cormack (1992, Biometrics48, 567,576). [source] Income Variance Dynamics and HeterogeneityECONOMETRICA, Issue 1 2004Costas Meghir Recent theoretical work has shown the importance of measuring microeconomic uncertainty for models of both general and partial equilibrium under imperfect insurance. In this paper the assumption of i.i.d. income innovations used in previous empirical studies is removed and the focus of the analysis is placed on models for the conditional variance of income shocks, which is related to the measure of risk emphasized by the theory. We first discriminate amongst various models of earnings determination that separate income shocks into idiosyncratic transitory and permanent components. We allow for education- and time-specific differences in the stochastic process for earnings and for measurement error. The conditional variance of the income shocks is modelled as a parsimonious ARCH process with both observable and unobserved heterogeneity. The empirical analysis is conducted on data drawn from the 1967,1992 Panel Study of Income Dynamics. We find strong evidence of sizeable ARCH effects as well as evidence of unobserved heterogeneity in the variances. [source] Mortgage Terminations, Heterogeneity and the Exercise of Mortgage OptionsECONOMETRICA, Issue 2 2000Yongheng Deng As applied to the behavior of homeowners with mortgages, option theory predicts that mortgage prepayment or default will be exercised if the call or put option is ,in the money' by some specific amount. Our analysis: tests the extent to which the option approach can explain default and prepayment behavior; evaluates the practical importance of modeling both options simultaneously; and models the unobserved heterogeneity of borrowers in the home mortgage market. The paper presents a unified model of the competing risks of mortgage termination by prepayment and default, considering the two hazards as dependent competing risks that are estimated jointly. It also accounts for the unobserved heterogeneity among borrowers, and estimates the unobserved heterogeneity simultaneously with the parameters and baseline hazards associated with prepayment and default functions. Our results show that the option model, in its most straightforward version, does a good job of explaining default and prepayment, but it is not enough by itself. The simultaneity of the options is very important empirically in explaining behavior. The results also show that there exists significant heterogeneity among mortgage borrowers. Ignoring this heterogeneity results in serious errors in estimating the prepayment behavior of homeowners. [source] The Labour Market Impact of the Working Families' Tax CreditFISCAL STUDIES, Issue 1 2000RICHARD BLUNDELL Abstract In October 1999, the working families' tax credit (WFTC) replaced family credit as the main package of in-work support for families with children. Among a range of stated aims, the WFTC is intended to,, improve work incentives, encouraging people without work to move into employment'. In this paper, we consider the impact of WFTC on hours and participation. To simulate labour supply responses, we use a discrete behavioural model of household labour supply with controls for fixed and childcare costs, and unobserved heterogeneity. In simulation, we experiment with a number of scenarios regarding the take-up of the credit, entry wage level and hourly childcare price. We find participation rates among single mothers to increase by around 2.2 percentage points for the base-case scenario, while for married women participation rates are modelled to fall. Our simulation results indicate a small increase in overall participation of around 30,000 individuals. [source] Always Poor or Never Poor and Nothing in Between?GERMAN ECONOMIC REVIEW, Issue 2 2010Duration of Child Poverty in Germany Child poverty; duration analysis; unobserved heterogeneity Abstract. This paper analyses the duration of child poverty in Germany. Observing the entire income history from the individuals' birth to their coming of age at age 18, we are able to analyse dynamics in and out of poverty for the entire population of children, whether they become poor at least once or not. Using duration models, we find that household composition, most importantly single parenthood, and the labour market status as well as level of education of the household head are the main driving forces behind exit from and re-entry into poverty and thus determine the (long-term) experience of poverty. [source] Dynamics of work limitation and work in AustraliaHEALTH ECONOMICS, Issue 6 2010*Article first published online: 5 JUN 200, Umut Oguzoglu Abstract This paper examines the impact of self-reported work limitations on the labour force participation of the Australian working age population. Five consecutive waves of the Household, Income and Labour Dynamics in Australia (HILDA) Survey are used to investigate this relationship. A two-equation dynamic panel data model demonstrates that persistence and unobserved heterogeneity play an important role in work limitation reporting and its effect on labour force participation. Unobserved factors that jointly drive work limitation and participation are also shown to be crucial, especially for women. Copyright © 2009 John Wiley & Sons, Ltd. [source] Modelling opportunity in health under partial observability of circumstancesHEALTH ECONOMICS, Issue 3 2010Pedro Rosa Dias Abstract This paper proposes a behavioural model of inequality of opportunity in health that integrates John Roemer's framework of inequality of opportunity with the Grossman model of health capital and demand for health. The model generates a recursive system of equations for health and lifestyles, which is then jointly estimated by full information maximum likelihood with freely correlated error terms. The analysis innovates by accounting for the presence of unobserved heterogeneity, therefore addressing the partial-circumstance problem, and by extending the examination of inequality of opportunity to health outcomes other than self-assessed health, such as long-standing illness, disability and mental health. The results provide evidence for the existence of third factors that simultaneously influence health outcomes and lifestyle choices, supporting the empirical relevance of the partial-circumstance problem. Accounting for these factors, the paper corroborates that the effect of parental and early circumstances on adult health disparities is paramount. However, the particular set of circumstances that affect each of the analysed health outcomes differs substantially. The results also show that differences in educational opportunities, and in social development in childhood, are crucial determinants of lifestyles in adulthood, which, in turn, shape the observed health inequalities. Copyright © 2010 John Wiley & Sons, Ltd. [source] Medical demography and intergenerational inequalities in general practitioners' earningsHEALTH ECONOMICS, Issue 9 2008B. Dormont Abstract This article examines the link between restrictions on the number of physicians and general practitioners' (GPs) earnings. Using a representative panel of 6016 French self-employed GPs over the years 1983,2004, we estimate an earnings function to identify experience, time and cohort effects. The estimated gap in earnings between ,good' and ,bad' cohorts can be as large as 25%. GPs who began their practices during the eighties have the lowest permanent earnings: they belong to the large cohorts of the baby-boom and face the consequences of an unlimited number of places in medical schools. Conversely, the decrease in the number of places in medical schools led to an increase in permanent earnings of GPs who began their practices in the mid-nineties. A stochastic dominance analysis shows that unobserved heterogeneity does not compensate for average differences in earnings between cohorts. These findings suggest that the first years of practice are decisive for a GP. If competition between physicians is too intense at the beginning of their careers, they will suffer from permanently lower earnings. To conclude, our results show that the policies aimed at reducing the number of medical students succeeded in buoying up physicians' permanent earnings. Copyright © 2008 John Wiley & Sons, Ltd. [source] Effects of ownership, subsidization and teaching activities on hospital costs in SwitzerlandHEALTH ECONOMICS, Issue 3 2008Mehdi Farsi Abstract This paper explores the cost structure of Swiss hospitals, focusing on differences due to teaching activities and those related to ownership and subsidization types. A stochastic total cost frontier with a Cobb,Douglas functional form has been estimated for a panel of 148 general hospitals over the six-year period from 1998 to 2003. Inpatient cases adjusted by DRG cost weights and ambulatory revenues are considered as two separate outputs. The adopted econometric specification allows for unobserved heterogeneity across hospitals. The results suggest that teaching activities are an important cost-driving factor and hospitals that have a broader range of specialization are relatively more costly. The excess costs of university hospitals can be explained by more extensive teaching activities as well as the relative complexity of the offered medical treatments from a teaching point of view. However, even after controlling for such differences university hospitals have shown a relatively low cost-efficiency especially in the first two or three years of the sample period. The analysis does not provide any evidence of significant efficiency differences across ownership/subsidy categories. Copyright © 2007 John Wiley & Sons, Ltd. [source] Schooling, cognitive ability and healthHEALTH ECONOMICS, Issue 10 2005M. Christopher Auld Abstract A large literature documents a strong correlation between health and educational outcomes. In this paper we investigate the role of cognitive ability in the health-education nexus. Using NLSY data, we show that one standard deviation increase in cognitive ability is associated with roughly the same increase in health as two years of schooling and that cognitive ability accounts for roughly one quarter of the association between schooling and health. Both schooling and ability are strongly associated with health at low levels but less related or unrelated at high levels. Estimates treating schooling as endogenous to health suggest that much of the correlation between schooling and health is attributable to unobserved heterogeneity; the causal effect of schooling on health is large only for respondents with low levels of schooling and low cognitive ability. An implication is that policies which increase schooling will only increase health to the extent that they increase the education of poorly-educated individuals. Subsidies to college education, for example, are unlikely to increase population health. Copyright © 2005 John Wiley & Sons, Ltd. [source] Latent class models for use of primary care: evidence from a British panelHEALTH ECONOMICS, Issue 9 2005Teresa Bago d'Uva Abstract This paper models access to and utilisation of primary care using data from the British Household Panel Survey for the period 1991,2001. A latent class panel data framework is adopted to model individual unobserved heterogeneity in a flexible way. Accounting for the panel structure of the data leads to a substantial improvement in fit, and permits the identification of latent classes of users of health care. Analysis by gender shows that men and women respond differently to some factors, in particular, to age and income. There is evidence of a positive impact of income on the probability of seeking primary care. This effect is especially significant in the case of women. For both genders, the marginal effect of income on the propensity to visit a GP is greater for individuals who are less likely to seek primary care. A latent class aggregated count data model for the number of GP visits classifies individuals in three latent classes and shows a positive income effect particularly amongst those with lower levels of utilisation. Copyright © 2005 John Wiley & Sons, Ltd. [source] Measuring horizontal inequity in Belgian health care using a Gaussian random effects two part count data modelHEALTH ECONOMICS, Issue 7 2004Tom Van Ourti Abstract We estimate the determinants of utilisation of physician and hospital services in Belgium using a one- and two-part panel count data model, and a one- and two-part pooled count data model. We conclude that the two-part panel count data model is most appropriate as it controls for unobserved heterogeneity and allows for a two-part decision-making process. The estimates of the determinants of utilisation of health care are then used to calculate indices of horizontal inequity. We find that inequity for general practitioner and hospital services is stable across time and in favour of low-income individuals, in the sense that, overall, they consume more than one would expect on the basis of their need, albeit the indices for hospital care are not significant. Horizontal equity applies to specialist care in all years, but from 1999 onwards, some evidence (although not statistically significant) of pro-rich inequity is found. Copyright © 2004 John Wiley & Sons, Ltd. [source] Fixed fees and physician-induced demand: A panel data study on French physiciansHEALTH ECONOMICS, Issue 9 2003Eric Delattre Abstract This paper investigates on the existence of physician-induced demand (PID) for French physicians. The test is carried out for GPs and specialists, using a representative sample of 4500 French self-employed physicians over the 1979,1993 period. These physicians receive a fee-for-services (FFS) payment and fees are controlled. The panel structure of our data allows us to take into account unobserved heterogeneity related to the characteristics of physicians and their patients. We use generalized method of moments (GMM) estimators in order to obtain consistent and efficient estimates. We show that physicians experience a decline of the number of consultations when they face an increase in the physician:population ratio. However this decrease is very slight. In addition, physicians counterbalance the fall in the number of consultations by an increase in the volume of care delivered in each encounter. Econometric results give a strong support for the existence of PID in the French system for ambulatory care. Copyright © 2003 John Wiley & Sons, Ltd. [source] Keeping nurses at work: a duration analysisHEALTH ECONOMICS, Issue 6 2002Tor Helge HolmåsArticle first published online: 9 AUG 200 Abstract A shortage of nurses is currently a problem in several countries, and an important question is therefore how one can increase the supply of nursing labour. In this paper, we focus on the issue of nurses leaving the public health sector by utilising a unique data set containing information on both the supply and demand side of the market. To describe the exit rate from the health sector we apply a semi-parametric hazard rate model. In the estimations, we correct for unobserved heterogeneity by both a parametric (Gamma) and a non-parametric approach. We find that both wages and working conditions have an impact on nurses' decision to quit. Furthermore, failing to correct for the fact that nurses' income partly consists of compensation for inconvenient working hours results in a considerable downward bias of the wage effect. Copyright © 2002 John Wiley & Sons, Ltd. [source] Does Network Care Prolong Work Absences?INDUSTRIAL RELATIONS, Issue 3 2006WILLIAM G. JOHNSON We used data on 120,000 workers with occupational injuries occurring in California, Connecticut, and Texas to analyze the effects of healthcare networks on postinjury durations of work absence. Controlling for selection and unobserved heterogeneity, work absences are shorter, all else equal, for network cases than for non-network cases. The shorter durations could reduce lost productivity by more than $3.8 million (a 9% reduction in work loss days for non-network cases) if network care were extended to the non-network cases in our sample. [source] Measuring state dependence in individual poverty histories when there is feedback to employment status and household compositionJOURNAL OF APPLIED ECONOMETRICS, Issue 7 2009Martin Biewen This paper argues that the assumption of strict exogeneity, which is usually invoked in estimating models of state dependence with unobserved heterogeneity, is violated in the poverty context as important variables determining contemporaneous poverty status, in particular employment status and household composition, are likely to be influenced by past poverty outcomes. Therefore, a model of state dependence is developed that explicitly allows for possible feedback effects from past poverty to future employment and household composition outcomes. Empirical results based on data from the German Socio-Economic Panel (GSOEP) suggest that there are indeed such feedback effects and that failure to take them into account may lead to biased estimates of the state dependence effect. Copyright © 2009 John Wiley & Sons, Ltd. [source] Semiparametric Bayesian inference for dynamic Tobit panel data models with unobserved heterogeneityJOURNAL OF APPLIED ECONOMETRICS, Issue 6 2008Tong Li This paper develops semiparametric Bayesian methods for inference of dynamic Tobit panel data models. Our approach requires that the conditional mean dependence of the unobserved heterogeneity on the initial conditions and the strictly exogenous variables be specified. Important quantities of economic interest such as the average partial effect and average transition probabilities can be readily obtained as a by-product of the Markov chain Monte Carlo run. We apply our method to study female labor supply using a panel data set from the National Longitudinal Survey of Youth 1979. Copyright © 2008 John Wiley & Sons, Ltd. [source] Deriving target selection rules from endogenously selected samplesJOURNAL OF APPLIED ECONOMETRICS, Issue 5 2006Bas Donkers The selection of the most profitable customers in a customer database for targeted activities is often done based on observed behaviour in the past. Consequently, databases arising from the responses to, for example, direct mailings in the past are not random samples. When not all heterogeneity across customers is observed, target selection will be based on unobserved heterogeneity and hence it is endogenous. We develop a method to adjust the likelihood function of latent class models to correct for this endogenous sampling process. We apply this technique to the selection of mail targets for a Dutch charity. Based on a joint model for the response rate and the amount donated, we create a target selection rule that maximizes expected revenues. Copyright © 2006 John Wiley & Sons, Ltd. [source] Transitions from home to marriage of young AmericansJOURNAL OF APPLIED ECONOMETRICS, Issue 1 2002Dr Arnstein Aassve The paper examines the impact of income on the transitions between home, living independently and first marriage of young Americans. A matching model is outlined, similar to that used in theories of job search, to explain the probability of marriage and living alone. A multiple-state, multiple-transition model which allows for correlated heterogeneity on the first and subsequent transitions is estimated. The results show that income has a strong and significant effect. The impact of unobserved heterogeneity is examined in detail. The impact of the young person's earnings on the transitions is explored through simulation. Copyright © 2002 John Wiley & Sons, Ltd. [source] SOME PRACTICAL GUIDANCE FOR THE IMPLEMENTATION OF PROPENSITY SCORE MATCHINGJOURNAL OF ECONOMIC SURVEYS, Issue 1 2008Marco Caliendo Abstract Propensity score matching (PSM) has become a popular approach to estimate causal treatment effects. It is widely applied when evaluating labour market policies, but empirical examples can be found in very diverse fields of study. Once the researcher has decided to use PSM, he is confronted with a lot of questions regarding its implementation. To begin with, a first decision has to be made concerning the estimation of the propensity score. Following that one has to decide which matching algorithm to choose and determine the region of common support. Subsequently, the matching quality has to be assessed and treatment effects and their standard errors have to be estimated. Furthermore, questions like ,what to do if there is choice-based sampling?' or ,when to measure effects?' can be important in empirical studies. Finally, one might also want to test the sensitivity of estimated treatment effects with respect to unobserved heterogeneity or failure of the common support condition. Each implementation step involves a lot of decisions and different approaches can be thought of. The aim of this paper is to discuss these implementation issues and give some guidance to researchers who want to use PSM for evaluation purposes. [source] Product-country images and preference heterogeneity for Mediterranean food products: A discrete choice frameworkAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 3 2005Riccardo Scarpa Despite the importance of region of origin (ROO) as a quality indicator and EU recognition of territorial specificity in food products, there is still a dearth of work investigating the importance of regional (both national and territorial) identity in consumer perceptions for specific food product categories. Employing nationwide discrete choice data for Italy, we investigate the strength of the ROO attribute across three food product categories. Moreover, in addition to treating taste heterogeneity as conditional on socioeconomic factors, we employ recent advances in discrete-choice modeling to test for unobserved heterogeneity in consumer preferences for domestic and territorial origin of production certification. The results show evidence of home bias in preference across all three food products, while preference heterogeneity is exhibited for table grapes and oil, but not for oranges. The analysis shows that unobserved heterogeneity, as represented by mixed logit models, appears to explain more of the observed choice variation than heterogeneity associated to socioeconomic characteristics. [JEL classification: Q120,Q130, Q180]. © 2005 Wiley Periodicals, Inc. Agribusiness 21: 329,349, 2005. [source] Does sex education affect adolescent sexual behaviors and health?JOURNAL OF POLICY ANALYSIS AND MANAGEMENT, Issue 4 2006Joseph J. SabiaArticle first published online: 6 SEP 200 This study examines whether offering sex education to young teenagers affects several measures of adolescent sexual behavior and health: virginity status, contraceptive use, frequency of intercourse, likelihood of pregnancy, and probability of contracting a sexually transmitted disease. Using data from the National Longitudinal Study of Adolescent Health, I find that while sex education is associated with adverse health outcomes, there is little evidence of a causal link after controlling for unobserved heterogeneity via fixed effects and instrumental variables. These findings suggest that those on each side of the ideological debate over sex education are, in a sense, both correct and mistaken. Opponents are correct in observing that sex education is associated with adverse health outcomes, but are generally incorrect in interpreting this relationship causally. Proponents are generally correct in claiming that sex education does not encourage risky sexual activity, but are incorrect in asserting that investments in typical schoolbased sex education programs produce measurable health benefits. © 2006 by the Association for Public Policy Analysis and Management [source] Overeducation and the skills of UK graduatesJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 2 2009Arnaud Chevalier Summary., During the early 1990s the proportion of a cohort entering higher education in the UK doubled over a short period of time. The paper investigates the effect of the expansion on graduates' early labour market attainment, focusing on overeducation. We define overeducation by combining occupation codes and a self-reported measure for the appropriateness of the match between qualification and the job. We therefore define three groups of graduates: matched, apparently overeducated and genuinely overeducated. This measure is well correlated with alternative definitions of overeducation. Comparing pre- and post-expansion cohorts of graduates, we find with this measure that the proportion of overeducated graduates has doubled, even though overeducation wage penalties have remained stable. We do not find that type of institution affects the probability of genuine overeducation. Apparently overeducated graduates are mostly indistinguishable from matched graduates, whereas genuinely overeducated graduates principally lack non-academic skills and suffer a large wage penalty. Individual unobserved heterogeneity differs between the three groups of graduates but controlling for it does not alter these conclusions. [source] Sibling death clustering in India: state dependence versus unobserved heterogeneityJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 4 2006Wiji Arulampalam Summary., Data from a range of environments indicate that the incidence of death is not randomly distributed across families but, rather, that there is a clustering of death among siblings. A natural explanation of this would be that there are (observed or unobserved) differences across families, e.g. in genetic frailty, education or living standards. Another hypothesis that is of considerable interest for both theory and policy is that there is a causal process whereby the death of a child influences the risk of death of the succeeding child in the family. Drawing language from the literature on the economics of unemployment, the causal effect is referred to here as state dependence (or scarring). The paper investigates the extent of state dependence in India, distinguishing this from family level risk factors that are common to siblings. It offers some methodological innovations on previous research. Estimates are obtained for each of three Indian states, which exhibit dramatic differences in socio-economic and demographic variables. The results suggest a significant degree of state dependence in each of the three regions. Eliminating scarring, it is estimated, would reduce the incidence of infant mortality (among children who are born after the first child) by 9.8% in the state of Uttar Pradesh, 6.0% in West Bengal and 5.9% in Kerala. [source] Can Nutritional Label Use Influence Body Weight Outcomes?KYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 4 2009Andreas C. Drichoutis SUMMARY Many countries around the world have already mandated, or plan to mandate, the presence of nutrition related information on most pre-packaged food products. Health advocates and lobbyists would like to see similar laws mandating nutrition information in the restaurant and fast-food market as well. In fact, New York City has already taken a step forward and now requires all chain restaurants with 15 or more establishments anywhere in US to show calorie information on their menus and menu board. The benefits were estimated to be as much as 150,000 fewer obese New Yorkers over the next five years. The implied benefits of the presence of nutrition information are that consumers will be able to observe such information and then make informed (and hopefully healthier) food choices. In this study, we use the latest available dataset from the US National Health and Nutrition Examination Survey (2005,2006) to explore whether reading such nutrition information really has an effect on body weight outcomes. In order to deal with the inherent problem of cross-sectional datasets, namely self-selection, and the possible occurrence of reverse causality we use a propensity score matching approach to estimate causal treatment effects. We conducted a series of tests related to variable choice of the propensity score specification, quality of matching indicators, robustness checks, and sensitivity to unobserved heterogeneity, using Rosenbaum bounds to validate our propensity score exercise. Our results generally suggest that reading nutrition information does not affect body mass index. The implications of our findings are also discussed. [source] Unemployment, Splitting up, and Spousal Income ReplacementLABOUR, Issue 1 2008William Nilsson The purpose is to estimate the possible income replacement that a female/male spouse can provide. Unemployment can also affect the probability that the couples split up. As not all couples remain in the analysis, a potential selection problem can occur. To deal with this problem, and also to handle unobserved heterogeneity, a sample selection model for panel data is estimated. Unemployment is not found to be correlated with a higher spousal income. [source] Modelling Currency Crises in Emerging Markets: A Dynamic Probit Model with Unobserved Heterogeneity and Autocorrelated Errors,OXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 4 2006Elisabetta Falcetti Abstract The paper investigates the causes of currency crises in emerging markets. We estimate the probability of a currency crisis by applying maximum smoothly simulated likelihood to a dynamic LDV model. This approach allows us to take explicit account of the existence of intertemporal links between crises. The results show that currency crises are influenced by real, monetary, debt and global variables. Past banking crises are significant determinants of the probability of currency crises. Moreover, countries that sharply devalued in the past are less prone to experience another currency crisis. We find evidence of unobserved heterogeneity, which may reflect differences in the countries' institutional/historical background. Finally, the determinants of currency crises differ by type of exchange rate regime. [source] Multiple mortality optima due to heterogeneity in the birth cohort: A continuous model of birth weight by gestational age-specific infant mortalityAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 4 2007Fu Fang Birth weight and gestational age are both important predictors of infant survival. Covariate Density Defined mixture of logistic regressions (CDDmlr), a method that accounts for unobserved heterogeneity, has been applied to birth outcomes using birth weight alone. This paper investigates a CDDmlr model of birth outcomes that includes birth weight and gestational age. Applications to four birth cohorts, composed of all non-Hispanic singleton African/European American female/male live births in New York State from 1985,1988, are presented. Multiple birth weight by gestational age optimal (minimal) mortalities are observed in the birth weight by gestational age-specific mortality surface. Multiple optima have not been mentioned in the published literature, but they do appear in some published plots of birth weight by gestational age mortality. It is possible that misreporting of gestational age contributes to this phenomenon, but it cannot completely explain the locations of the local optima. The global optimum is associated with a "normal" fetal development subpopulation, while the local optima are due to a subpopulation that accounts for most low birth weight, intrauterine growth retarded, pre-term, post-term, and small for gestational age births, as well as, births with misestimated gestational ages. These two subpopulations have significantly different birth weight by gestational age-specific mortality surfaces. Consequently, the presence of multiple optima can be attributed to heterogeneity in the birth cohort. Comparisons of CDDmlr based on birth weight by gestational age and birth weight alone might statistically identify births with "erroneous" gestational age. Am. J. Hum. Biol. 19:475,486, 2007. © 2007 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||