Analyzing yield, duration and convexity of mortgage loans under prepayment and default risks

In this article, we construct a general model, which considers the borrower’s financial and non-financial termination behavior, to derive the closed-form formula of the mortgage value for analyzing the yield, duration and convexity of the risky mortgage. Since the risks of prepayment and default are reasonably expounded in our model, our formulae are more appropriate than traditional mortgage formulae. We also analyze the effects of the prepayment penalty and partial prepayment on the yield, duration and convexity of a mortgage, and provide lenders with an upper-bound for the mortgage default insurance rate. Our model provides portfolio managers a useful framework to more appropriately appraise the mortgage and more effectively hedge their mortgage holdings. From the results of sensitivity analyses, we find that higher interest-rate, prepayment and default risks will increase the mortgage yield and reduce the duration and convexity of the mortgage.     

Order preserving functions and generalized convexity

In order to better understand the monotonicity properties which characterize the gradient of pseudoconvex and quasi convex funzions, psedomonotonicity and quasi monotonicity can be introduced. A quite different approach is proposed in this paper, by defining new order relations, whose preservation leads precisely to several kinds of pseudoconvexity and quasi convexity. Some general properties of order preservation are proved; they are useful to state necessary and sufficient conditions of monotonicity for particular orders related with generalized convexity.     

Computation in duration models with heterogeneity

This paper examines the use of Hermite polynomial quadrature to evaluate certain integrals in the maximum likelihood estimation of duration models.     

Discrete time duration models with group-level heterogeneity

Dynamic discrete choice panel data models have received a great deal of attention. In those models, the dynamics is usually handled by including the lagged outcome as an explanatory variable. In this paper we consider an alternative model in which the dynamics is handled by using the duration in the current state as a covariate. We propose estimators that allow for group-specific effect in parametric and semiparametric versions of the model. The proposed method is illustrated by an empirical analysis of job durations allowing for firm-level effects.     

Nonparametric function estimation subject to monotonicity, convexity and other shape constraints

This paper uses free-knot and fixed-knot regression splines in a Bayesian context to develop methods for the nonparametric estimation of functions subject to shape constraints in models with log-concave likelihood functions. The shape constraints we consider include monotonicity, convexity and functions with a single minimum. A computationally efficient MCMC sampling algorithm is developed that converges faster than previous methods for non-Gaussian models. Simulation results indicate the monotonically constrained function estimates have good small sample properties relative to (i) unconstrained function estimates, and (ii) function estimates obtained from other constrained estimation methods when such methods exist. Also, asymptotic results show the methodology provides consistent estimates for a large class of smooth functions. Two detailed illustrations exemplify the ideas.     

Rent control and tenancy duration

This paper investigates how rent control affects mobility in the Danish housing market. We apply a proportional hazard duration model, that encompasses both the presence of left truncated tenancy durations, right censored observations and allows for a very flexible specification of the time dependency of the hazard rate. Tenancy mobility is severely reduced by rent control. For a typical household in the private rental sector tenancy duration is found to be more than six years longer if the apartment belongs to the 10% most regulated units than if it belongs to the 10% least regulated units.     

Measuring the duration of emotional experience: the influence of actual duration and response format

In a number of retrospective studies it has been found that the duration of emotional experience is highly variable and several determinants that account for this variability have been identified. However, two issues that may have consequences for the measurement of emotion duration have been left unaddressed. First, it is unclear whether people are capable of remembering the duration of their actual emotional experience. Second, it is uncertain whether estimates of the duration of emotional experience are influenced by the format of the response scale. Participants watched joy- and sadness-sustaining movie fragments of different durations. At the end of the day they were asked to estimate the duration of each fragment or the duration of their emotions during each fragment on a relatively short-range or long-range scale. Regardless of whether fragment or emotion duration was estimated, estimates were (a) largely accurate and (b) higher on long-range compared to short-range scales.     

Partial rank estimation of duration models with general forms of censoring

In this paper we propose estimators for the regression coefficients in censored duration models which are distribution free, impose no parametric specification on the baseline hazard function, and can accommodate general forms of censoring. The estimators are shown to have desirable asymptotic properties and Monte Carlo simulations demonstrate good finite sample performance. Among the data features the new estimators can accommodate are covariate-dependent censoring, double censoring, and fixed (individual or group specific) effects. We also examine the behavior of the estimator in an empirical illustration.     

Guaranteed minimum income and unemployment duration in France

In this article, we use data from the European Community Household Panel to evaluate the impact of a French guaranteed income program, the RMI, on the hazard out of unemployment. Self-selection into the program is corrected using a multivariate duration model developed by [Abbring, J.H., van den Berg, G.J., 2003. The non-parametric identification of treatment effects in duration models. Econometrica 71 (5), 1491–1517]. We find that RMI receipt has a strong negative impact during the first months of program participation, but that this disincentive effect quickly falls to insignificant levels after six months. Household structure also appears to be an important determinant of the importance of the adverse effect of program participation.     

Wage curve, unemployment duration and compensating differentials

In this study unemployment effects on individual pay are investigated following the study on ‘wage curves’ by Blanchflower and Oswald (1990). In bargaining models, higher unemployment should lower wage pressure; due to compensating wage differential arguments, on the other hand, workers who take jobs with higher layoff risks should be rewarded. In a cross-sectional study on Austrian data, a negative wage curve is confirmed. Contrary to the results by Blanchflower and Oswald no U-shape is found, also long-term unemployment seems to be important. No conclusive evidence of compensating differentials has been determined.     

A Markov-switching multifractal inter-trade duration model,with application to US equities

We propose and illustrate a Markov-switching multifractal duration (MSMD) model for analysis of inter-trade durations in financial markets. We establish several of its key properties with emphasis on high persistence and long memory. Empirical exploration suggests MSMD’s superiority relative to leading competitors.     

Ethnic polarization and the duration of civil wars

In this paper we analyze the relationship between ethnic polarization and the duration of civil wars. Several recent papers have argued that the uncertainty about the relative power of the contenders in a war will tend to increase its duration. In these models, uncertainty is directly related to the relative size of the contenders. We argue that the duration of civil wars increases the more polarized a society is. Uncertainty is not necessarily linked to the structure of the population but it could be traced back to the measurement of the size of the different groups in the society. Given a specific level of measurement error or uncertainty, more polarization implies lengthier wars. Our empirical results show that ethnically polarized countries have to endure longer civil wars than ethnically less polarized societies.     

基于改进GQPSO算法的多目标卷烟配送策略

卷烟配送普遍呈现客户点多、路线复杂的特点,是典型的组合NP难题。以配送成本最低且配送量均衡为优化目标,建立带时间窗的卷烟配送通用数学模型;引入选择与交叉操作,提出运用改进的遗传量子粒子群算法（GQPSO）实现车辆编号和配送次序同步寻优,以制定卷烟配送的最优策略。实例表明：GQPSO能快速有效制定满足优化目标的卷烟配送策略。     

Modified lagrange multiplier tests for problems with one-sided alternatives

A modified Lagrange multiplier test statistic is proposed which takes explicit account of the one-sided nature of the alternative in problems where the null hypothesis specifies that the true value of the parameter vector lies on the boundary of the parameter space. Computation of this statistic requires only the constrained maximum likelihood estimator. Conditions for the consistency of tests based on this statistic are examined and it is shown that the distribution of the statistic is not affected of nuisance parameters are allowed to lie on the boundary of the parameter space.     

Layoffs and duration dependence in a model of turnover

A semi-Markov model of turnover, resulting from optimizing behavior on the part of workers, is developed. Duration dependence in the transition out of employment is modelled as resulting from a layoff probability which decreases with tenure. Some preliminary results, based on DIME data, are presented. These indicate that a declining hazard rate in the transition out of employment is a significant feature of the data.     

Time aggregation and the distributional shape of unemployment duration

This paper reports empirical evidence on the sensitivity of unemployment duration regression estimates to distributional assumptions and to time aggregation. The results indicate that parameter estimates are robust to distributional assumptions, while estimates of duration dependence are not. Time aggregation does not seem to have drastic effects on the estimates in a simple parametric model like the Weibull, but can produce dramatic changes in the more complicated extended generalized gamma model. Semiparametric models for grouped data produce stable estimates, and perform much better than continuous-time models in terms of significance at high levels of time aggregation.     

Epidemics and macroeconomic outcomes: Social distancing intensity and duration

We analyze the determination of the optimal intensity and duration of social distancing policy aiming to control the spread of an infectious disease in a simple macroeconomic–epidemiological model. In our setting the social planner wishes to minimize the social costs associated with the levels of disease prevalence and output lost due to social distancing, both during and at the end of epidemic management program. Indeed, by limiting individuals’ ability to freely move or interact with others (since requiring to wear face mask or to maintain physical distance from others, or even forcing some businesses to remain closed), social distancing has on the one hand the effect to reduce the disease incidence and on the other hand to reduce the economy’s productive capacity. We analyze both the early and the advanced epidemic stage intervention strategies highlighting their implications for short and long run health and macroeconomic outcomes. We show that both the intensity and the duration of the optimal social distancing policy may largely vary according to the epidemiological characteristics of specific diseases, and that the balancing of the health benefits and economic costs associated with social distancing may require to accept the disease to reach an endemic state. Focusing in particular on COVID-19 we present a calibration based on Italian data showing how the optimal social distancing policy may vary if implemented at national or at regional level.     

Unemployment duration and the interactions between unemployment insurance and social assistance

Existing studies suggest that reforms that reduce the generosity of the unemployment benefits should lower unemployment. Despite the large number of such reforms implemented in Europe in the past decades, evidence from various data sources shows very little correlation with the evolution of unemployment. This paper suggests that the scant success of these labour market reforms can be explained by the interactions between unemployment insurance and other social assistance programmes. Evidence from the European Community Household Panel shows that recipients of unemployment insurance who are also eligible for other welfare schemes are indeed less sensitive to changes in the level and the duration of their benefits.     

Timing and duration effects in residence histories and other longitudinal data: II. Studies of duration effects in Norway, 1965-1971

The main results of eleven studies of the nature and determinants of the timing of moves and duration of residence effects are presented. The studies (see table 1) illustrate the use of the methodological framework for studying individual histories of the previous article. There are substantial duration of residence effects in most population subgroups, implying that the migration process in non-Markovian at the mocro level and that the semi-Markov model is required. However, characterization of effects and their determinants are shown to depend so heavily on the type of interval and observation scheme used, that only within a comprehensive framework is proper interpretation of empirical results possible.     

Contract duration and contractual learning: Evidence from franchising networks

Contract duration in franchising has generally been studied in frameworks where agents are assumed to have a high level of foresight. We complement existing studies by adopting a dynamic perspective that allows us to introduce a learning process in choice and adjustment of contract duration. On the basis of French panel data (1995–2003), collected from the yearbooks of the French Federation of Franchising, results of dynamic models are consistent with the existence of a learning process in the capacity to design appropriate contracts. Our study shows that certain factors, in particular too much franchising, may hinder the achievement of such a capability.