MULTILEVEL DISCRETE‐TIME EVENT HISTORY MODELS WITH APPLICATIONS TO THE ANALYSIS OF RECURRENT EMPLOYMENT TRANSITIONS

Data on the timing of events such as births, residential moves and changes in employment status are collected in many longitudinal surveys. These data often have a highly complex structure, with events of several types occurring repeatedly over time to an individual and interdependences between different event processes (e.g. births and employment transitions). The aim of this paper is to review a general class of multilevel discrete‐time event history models for handling recurrent events and transitions between multiple states. It is also shown how standard methods can be extended to allow for time‐varying covariates that are outcomes of an event process that is jointly determined with the process of interest. The considerable potential of these methods for studying transitions through the life course is illustrated in analyses of the effect of the presence and age of children on women's employment transitions, using data from the British Household Panel Survey.     

The formation and outcomes of cohabiting and marital partnerships in early adulthood: the role of previous partnership experience

Summary.  We estimate a joint model of the formation and dissolution of cohabiting and marital unions among British women who were born in 1970. The focus of the analysis is the effect of previous cohabitation and marriage on subsequent partnership transitions. We use a multilevel simultaneous equations event history model to allow for residual correlation between the hazards of moving from an unpartnered state into cohabitation or marriage, converting a cohabiting union into marriage and dissolution of either form of union. A simultaneous modelling approach allows for the joint determination of these transitions, which may otherwise bias estimates of the effects of previous partnership outcomes on later transitions.     

Estimating low pay transition probabilities accounting for endogenous selection mechanisms

Summary.  We propose a model of transitions into and out of low paid employment that accounts for non-ignorable panel dropout, employment retention and base year low pay status ('initial conditions'). The model is fitted to data for men from the British Household Panel Survey. Initial conditions and employment retention are found to be non-ignorable selection processes. Whether panel dropout is found to be ignorable depends on how item non-response on pay is treated. Notwithstanding these results, we also find that models incorporating a simpler approach to accounting for non-ignorable selections provide estimates of covariate effects that differ very little from the estimates from the general model.     

Intergenerational fertility changes

Intergenerational changes in fertility in Poland are analyzed using data from a 1977 sample survey of 38,600 women. The author notes that total fertility declined from 4.4 to 2.5 within the space of two generations. An analysis of fertility is presented by various characteristics of females, including age group, education, duration of marriage, and economic status.     

Comment

Bonferroni inequalities often provide tight upper and lower bounds for the probability of a union of events. The bounds are especially useful when this probability is difficult to compute exactly. There are situations, however, in which the Bonferroni approach gives very poor results. An example is given in which the upper and lower Bonferroni bounds are far from the probability they seek to approximate and successive bounds do not converge. Even an improved first upper Bonferroni bound may not be close to the probability of the union of events.     

The demographic transformation--a challenge to labor market and social policies

The implications of future demographic trends for labor market and social policies in the Federal Republic of Germany are discussed. The focus is on how trends such as demographic aging and declining fertility will affect the labor market, employment, and old-age security.     

A Bayesian Approach to Model Interdependent Event Histories by Graphical Models

In event history analysis, the problem of modeling two interdependent processes is still not completely solved. In a frequentist framework, there are two most general approaches: the causal approach and the system approach. The recent growing interest in Bayesian statistics suggests some interesting works on survival models and event history analysis in a Bayesian perspective. In this work we present a possible solution for the analysis of dynamic interdependence by a Bayesian perspective in a graphical duration model framework, using marked point processes. Main results from the Bayesian approach and the comparison with the frequentist one are illustrated on a real example: the analysis of the dynamic relationship between fertility and female employment.     

How Do Behavioral Assumptions Affect Structural Inference? Evidence From a Laboratory Experiment

We develop a model of labor force status (federal employment, nonfederal employment, unemployment, and out of the labor force) that depends on human capital variables, local labor market conditions, and personal characteristics. According to the estimated model for white non-Hispanic males and females a substantial difference exists between blacks and white non-Hispanics even after correction for the control variables. However, the control variables explain almost all of the difference between Hispanics and white non-Hispanics.     

Confidence Bands for Comparison of Transition Probabilities in a Markov Chain Model

We consider graphs, confidence procedures and tests that can be used to compare transition probabilities in a Markov chain model with intensities specified by a Cox proportional hazard model. Under assumptions of this model, the regression coefficients provide information about the relative risks of covariates in one–step transitions, however, they cannot in general be used to to assess whether or not the covariates have a beneficial or detrimental effect on the endpoint events. To alleviate this problem, we consider graphical tests based on confidence procedures for a generalized Q–Q plot and for the difference between transition probabilities. The procedures are illustrated using data of the International Bone Marrow Transplant Registry.     

Assessing the use of sample selection models in the estimation of fertility postponement effects

Several studies have shown that at the individual level there exists a negative relationship between age at first birth and completed fertility. Using twin data in order to control for unobserved heterogeneity as possible source of bias, Kohler et al. (2001) showed the significant presence of such "postponement effect" at the micro level. In this paper, we apply sample selection models, where selection is based on having or not having had a first birth at all, to estimate the impact of postponing first births on subsequent fertility for four European nations, three of which have now lowest-low fertility levels. We use data from a set of comparative surveys (Fertility and Family Surveys), and we apply sample selection models on the logarithm of total fertility and on the progression to the second birth. Our results show that postponement effects are only very slightly affected by sample selection biases, so that sample selection models do not improve significantly the results of standard regression techniques on selected samples. Our results confirm that the postponement effect is higher in countries with lowest-low fertility levels.     

The analysis of age-specific fertility patterns via logistic models

In this paper, we introduce logistic models to analyse fertility curves. The models are formulated as linear models of the log odds of fertility and are defined in terms of parameters that are interpreted as measures of level, location and shape of the fertility schedule. This parameterization is useful for the evaluation, and interpretation of fertility trends and projections of future period fertility. For a series of years, the proposed models admit a state-space formulation that allows a coherent joint estimation of parameters and forecasting. The main features of the models compared with other alternatives are the functional simplicity, the flexibility, and the interpretability of the parameters. These and other features are analysed in this paper using examples and theoretical results. Data from different countries are analysed, and to validate the logistic approach, we compare the goodness of fit of the new model against well-known alternatives; the analysis gives superior results in most developed countries.     

The importance of intentions in the mechanism of reproductive behaviour formation

In a situation of low fertility like that operating nowadays, studying the determinants of reproductive behaviour is very important. In a context such as Western industrialized one, in which birth control induces a feature of consciousness into fertility conduct, reproductive intentions have a fundamental role. This paper examines the mechanism which leads to the formation of reproductive behaviour starting from intentions, with reference to a large city in Italy, where fertility is very low, Milan. In addition, the hypothesis that women have innate and unobservable propensities toward family formation is verified through a simultaneous equations model. It allows to control for the potential endogeneity of reproductive intentions in determining subsequent behaviour. Results partially confirm this hypothesis: no significant correlation is found between unobservable components influencing intentions and behaviour. The relevance of reproductive intentions for subsequent fertility behaviour is, however, pointed out.     

Simulation and extremal analysis of hurricane events

In regions affected by tropical storms the damage caused by hurricane winds can be catastrophic. Consequently, accurate estimates of hurricane activity in such regions are vital. Unfortunately, the severity of events means that wind speed data are scarce and unreliable, even by standards which are usual for extreme value analysis. In contrast, records of atmospheric pressures are more complete. This suggests a two-stage approach: the development of a model describing spatiotemporal patterns of wind field behaviour for hurricane events; then the simulation of such events, using meteorological climate models, to obtain a realization of associated wind speeds whose extremal characteristics are summarized. This is not a new idea, but we apply careful statistical modelling for each aspect of the model development and simulation, taking the Gulf and Atlantic coastlines of the USA as our study area. Moreover, we address for the first time the issue of spatial dependence in extremes of hurricane events, which we find to have substantial implications for regional risk assessments.     

A new behavioural model for fertility schedules

Modelling age-specific fertility rates is of great importance in demography because of their influence on population growth. Although we have a variety of fertility models in the demographic literature, most of them do not have any demographic interpretation for their parameters. It is generally expected that models with behavioural interpretation are more universal than those without any interpretation. Even though the famous Gompertz model has some behavioural interpretation it suffers from other drawbacks. In the present work, we propose a new fertility model, which has its genesis in the generalization of logistic law. The proposed model has good behavioural interpretation, alongside having nice parameter interpretations.     

Testing for state dependence in binary panel data with individual covariates by a modified quadratic exponential model

We propose a test for state dependence in binary panel data with individual covariates. For this aim, we rely on a quadratic exponential model in which the association between the response variables is accounted for in a different way with respect to more standard formulations. The level of association is measured by a single parameter that may be estimated by a Conditional Maximum Likelihood (CML) approach. Under the dynamic logit model, the conditional estimator of this parameter converges to zero when the hypothesis of absence of state dependence is true. Therefore, it is possible to implement a t-test for this hypothesis which may be very simply performed and attains the nominal significance level under several structures of the individual covariates. Through an extensive simulation study, we find that our test has good finite sample properties and it is more robust to the presence of (autocorrelated) covariates in the model specification in comparison with other existing testing procedures for state dependence. The proposed approach is illustrated by two empirical applications: the first is based on data coming from the Panel Study of Income Dynamics and concerns employment and fertility; the second is based on the Health and Retirement Study and concerns the self reported health status.     

Reduced rank proportional hazards model for competing risks: An application to a breast cancer trial

In many cancer trials patients are at risk of recurrence and death after the appearance and the successful treatment of the first diagnosed tumour. In this situation competing risks models that model several competing causes of therapy or surgery failure are a natural framework to describe the evolution of the disease.Typically, regression models for competing risks outcomes are based on proportional hazards model for each of the cause-specific hazard rates. An immediate practical problem is then how to deal with the abundance of regression parameters. The aim of reduced rank proportional hazards models is to reduce the number of parameters that need to be estimated while at the same time keeping the distinction between different transitions. They have the advantage of describing the competing risks model in fewer parameters, cope with transitions where few events are present and facilitate the interpretation of these estimates.We shall illustrate the use of this technique on 2795 patients from a breast cancer trial (EORTC 10854).     

The Effects of Variations in the Components of Change on the Size and Structure of The Australian Population: 1911-66

The main aim of the study was to estimate separately the effects of the variations in the components of population change and the effects of their mutual interactions on the size and age structure and other characteristics of the Australian population during 1911-66. The method proposed, called here the factorial projection method, is to project the population over the period under consideration, under different assumptions according to a 2×2×2 factorial design, utilizing the observed variations in fertility, mortality and migration. It was found that, apart from the effects of variations in the components occurring individually, the two factor interaction effects– the interaction effects of the changes occurring simultaneously in two of the components (viz. fertility and mortality or mortality and migration or fertility and migration)–on the population size, were considerable. The contribution of migration to the working age group was greater than its effect on the total size, and mortality improvement played a more prominent role in increasing the size of the old age population, while the reduction in fertility caused a higher proportion in the old age group and thus increased the mean age of the population both in the case of males and females. The two factor interaction effects were not negligible in changing the size of the school age population, population in the working age group and also in the old age group. But the interaction of migration and the decline in fertility was the only interaction effect which was important in changing the percentage age distribution and the mean age of the male and female population.     

中国老年人低就业率成因:与俄罗斯的跨国比较

在老龄化加速和劳动年龄人口下降的背景下,开发我国老年劳动力资源具有重要意义。本文基于1988-2013年住户调查数据,通过与俄罗斯较长时期的跨国比较,发现中国老年人就业率偏低且持续下降,并进一步利用Oaxaca方法分解了就业率下降的贡献来源,由此解释了中国城镇老年人就业率较低的原因。研究发现,文化和制度因素的影响并不显著,而劳动力市场禀赋及其分化才是我国老年人就业率较低且持续下降的主要原因。相对于俄罗斯,中国城镇居民财富积累更快,收入结构更加多元化,再加上年轻外来劳动力涌入形成的挤出效应,带来中国老年人就业意愿和就业竞争力的双重下降,由此就使得中国老年人就业率逐渐降低。因此要打破劳动力市场分割,让老年劳动力顺利实现职业转换和工作岗位转变;改善小微企业营商环境,扩大老年人非正规就业机会;增加老年人职业培训以提高就业竞争力,鼓励获得较高教育技能的老年人工作更长的年限,并成为劳动力市场的重要补充。     

Multi-state Models: A Review

Multi-state models are models for a process, for example describing a life history of an individual, which at any time occupies one of a few possible states. This can describe several possible events for a single individual, or the dependence between several individuals. The events are the transitions between the states. This class of models allows for an extremely flexible approach that can model almost any kind of longitudinal failure time data. This is particularly relevant for modeling different events, which have an event-related dependence, like occurrence of disease changing the risk of death. It can also model paired data. It is useful for recurrent events, but has limitations. The Markov models stand out as much simpler than other models from a probability point of view, and this simplifies the likelihood evaluation. However, in many cases, the Markov models do not fit satisfactorily, and happily, it is reasonably simple to study non-Markov models, in particular the Markov extension models. This also makes it possible to consider, whether the dependence is of short-term or long-term nature. Applications include the effect of heart transplantation on the mortality and the mortality among Danish twins.     

Decline and fall: Unemployment among Britain's non-white ethnic communities 1960–1999

The declining employment fortunes of Britain's non-white communities, relative to whites, are explained. To achieve this comparison, some historical official sources of unemployment data are reviewed. The earliest known official time series on unemployment of non-whites dates back to 1960. This historical context is explored, especially the reluctance to make the early data more widely known. An unemployment series for non-white males and females from 1970 to 1999 is derived in two separate ways by splicing together official sources. These series are compared with unemployment of whites to demonstrate a relative increase in unemployment of non-whites.