Maximum likelihood estimation in the proportional hazards model of random censorship

The maximum likelihood estimator (MLE) for the survival function S_Tunder the proportional hazards model of censorship is derived and shown to differ from the Abdushukurov-Cheng-Lin estimator when the class of allowable distributions includes all continuous and discrete distributions. The estimators are compared via an example. The MLE is calculated using a Newton-Raphson iterative procedure and implemented via a FORTRAN algorithm.     

CORRECTING FOR KURTOSIS IN DENSITY ESTIMATION

Using a global window width kernel estimator to estimate an approximately symmetric probability density with high kurtosis usually leads to poor estimation because good estimation of the peak of the distribution leads to unsatisfactory estimation of the tails and vice versa. The technique proposed corrects for kurtosis via a transformation of the data before using a global window width kernel estimator. The transformation depends on a “generalised smoothing parameter” consisting of two real-valued parameters and a window width parameter which can be selected either by a simple graphical method or, for a completely data-driven implementation, by minimising an estimate of mean integrated squared error. Examples of real and simulated data demonstrate the effectiveness of this approach, which appears suitable for a wide range of symmetric, unimodal densities. Its performance is similar to ordinary kernel estimation in situations where the latter is effective, e.g. Gaussian densities. For densities like the Cauchy where ordinary kernel estimation is not satisfactory, our methodology offers a substantial improvement.     

Economic determinants of fertility: Results from cross sectional aggregate data

Census data for areal units, SMSA’s in 1960 and cities in 1940, are used to test hypotheses and estimate parameters concerning the influence of a variety of socioeconomic variables on fertility rates of ever married white and nonwhite women aged 25–29, 30–34, 35–44, and 45–49. An economic model of the demand for children is adopted as the theoretical framework. The principal findings are that the market earnings opportunities for wives have an important negative effect on the fertility rate and that male income, representing the income of husbands, has a small but positive effect on fertility. The implication of these results is that changes in economic variables, for example, improvements in the employment opportunities and wages for wives or the establishment of a children’s allowance program, may be expected to affect fertility.     

Gaussian-based kernels

We derive a class of higher-order kernels for estimation of densities and their derivatives, which can be viewed as an extension of the second-order Gaussian kernel. These kernels have some attractive properties such as smoothness, manageable convolution formulae, and Fourier transforms. One important application is the higher-order extension of exact calculations of the mean integrated squared error. The proposed kernels also have the advantage of simplifying computations of common window-width selection algorithms such as least-squares cross-validation. Efficiency calculations indicate that the Gaussian-based kernels perform almost as well as the optimal polynomial kernels when die order of the derivative being estimated is low.     

Admissible estimators in finite population sampling employing various types of prior information

We consider some estimators of the total and variance of a finite population from Bayesian and pseudo-Bayesian perspectives. Recently, Meeden and Ghosh (1982a, 1982b) have provided quite simple but powerful tools for proving admissibility of estimators and estimator-design pairs is finite population sampling problems. We consider what these techniques yield in the way of admissibility results for the estimators discussed.     

Extending monetary values to broader performance and impact measures: Transportation applications and lessons for other fields

This article examines recent progress at assigning monetary values to what are normally considered “hard to quantify” benefits of transportation projects. It focuses on three types of impacts – environmental quality, health and wider economic impacts – to examine how transportation project evaluation methods have evolved in recent years and how they compare to methods used for evaluation of non-transportation programs. Examples of recent practice are provided to show how transport agencies are continuing to refine performance measures to include broader impacts in project evaluation. A classification is provided to distinguish direct traveler effects from indirect effects on non-travelers, a step important to maximize coverage and minimize double-counting of impacts. For each type of impact, the paper discusses the range of variation in monetized values and shows that the variation is due less to imprecision in measurement than to fundamental issues about whether to use damage compensation, impact avoidance costs, stated preferences or behavioral valuation perspectives to define those values. Case studies as diverse as Australian roads, Wisconsin energy programs and Appalachian economic development programs are used to show how common methods are evolving among transport and non-transport agencies to improve impact measurement and its use in project evaluation.     

The elephant in the room is awake and takes things personally: The North Korean nuclear threat and the general public's estimation of American diplomacy

The general audience for a global crisis can become a grassroots force in the ultimate fate of policy decisions. Focusing on the North Korean nuclear crisis case, certain contingent factors (dominant coalition characteristics, external threat, and external public characteristics) were overall strong predictors for public estimation about the government stance. Further, perception of situational factors (external threat and external public characteristics) was a stronger predictor for the participants’ stance estimation than perception of predisposing factors (dominant coalition characteristics). Implications for international diplomacy were discussed.     

An Empirical Approach to the Study of Well-being Among Rural Men and Women in Ghana

The paper indicates using community development and sustainable livelihood theories as lenses that well-being indicators vary among societies, especially in developing countries due cultural differences. The study which was carried in three rural communities in Ho Municipality in the Ghana was to show the extent to which men’s and women’s sense of well-being were determined by their local economic, religious, social, and education indicators; all of which were driven by their cultural values. Since men and women placed different values on religious, social, economic, education indicators, the paper discusses that their importance to overall well-being also differs between men and women.