Disparities in socio-economic outcomes: some positive propositions and their normative implications

Demographic disparities between the rates of occurrence of an adverse economic outcome can be observed to be increasing even as general social improvements supposedly lead towards the elimination of the adverse outcome in question. Scanlan (Chance 19(2):47–51, 2006) noticed this tendency and developed a ‘heuristic rule’ to explain it. In this paper, we explore the issue analytically, providing a criterion from stochastic ordering theory under which one of two demographic groups can be considered disadvantaged and the other advantaged, and showing that Scanlan’s heuristic obtains as a rigorous finding in such cases. Normative implications and appropriate social policy are discussed.     

Impact of customer loyalty and service operations on customer behaviour and firm performance: empirical evidence from UK retail sector

Abstract

Retail networks are striving to achieve competitive advantage by increasing value through loyalty and efficiency with a focus on service operations. As sales promotions have become an integral part of the retail supply chain planning, customer behavioural aspects based on loyalty and service operations have been challenged greatly. Subsequently, management capabilities, such as planning and timely replenishment, have become complicated tasks for many retail store managers. This study develops a model integrating retail network value and efficiencies with customer behaviour and performance. We validate the model using survey data from prominent U.K. retail store customers. Our data analysis shows that both loyalty and service operation attributes have positive significant impact on customer behaviour, while the service operation mediates the relationship between loyalty and customer behaviour. This result gives a new outlook to build managerial capability based on customer loyalty and service operations. Our results specifically show that the service operation attributes will indirectly influence the customers’ buying behaviour even in the presence of loyalty attribute such as promotion schemes. This result sends a strong signal to retail supply chain managers to offer customised promotions considering local community rather than having uniform sales promotion nationwide.     

Product-limit Estimators and Cox Regression with Missing Censoring Information

The Kaplan–Meier estimator of a survival function requires that the censoring indicator is always observed. A method of survival function estimation is developed when the censoring indicators are missing completely at random (MCAR). The resulting estimator is a smooth functional of the Nelson–Aalen estimators of certain cumulative transition intensities. The asymptotic properties of this estimator are derived. A simulation study shows that the proposed estimator has greater efficiency than competing MCAR-based estimators. The approach is extended to the Cox model setting for the estimation of a conditional survival function given a covariate.     

One mathematics for all: can it be realized in a multicultural,multilingual country?

In this paper, situated in the context of elementary and secondary school mathematics curriculum in India, I argue that centrally determined uniform curriculum would have very little to offer a large majority of students in a country that is diverse in many ways.     

Model-based confidence bands for survival functions

This paper focuses on a novel method of developing one-sample confidence bands for survival functions from right censored data. The approach is model-based, relying on a parametric model for the conditional expectation of the censoring indicator given the observed minimum, and derives its strength from easy access to a good-fitting model among a plethora of choices available for binary response data. The substantive methodological contribution is in exploiting a semiparametric estimator of the survival function to produce improved simultaneous confidence bands. To obtain critical values for computing the confidence bands, a two-stage bootstrap approach that combines the classical bootstrap with the more recent model-based regeneration of censoring indicators is proposed and a justification of its asymptotic validity is also provided. Several different confidence bands are studied using the proposed approach. Numerical studies, including robustness of the proposed bands to misspecification, are carried out to check efficacy. The method is illustrated using two lung cancer data sets.     

Identifying and controlling for program-level differences in comparative cost analysis: lessons from the economic evaluation of the National Breast and Cervical Cancer Early Detection Program

Performing economic evaluations of established health care programs is essential to identify and control for underlying program-level variations and to make valid comparisons. At a time when the need for such evaluations is growing, health care professionals have limited information on the methodological challenges of performing these evaluations. In this study, we used the National Breast and Cervical Cancer Early Detection Program to illustrate these potential underlying variations. We performed site visits to four grantees and collected activity-based cost data from nine additional representative programs. We identified five specific types of cost factors that should be considered when evaluating and comparing health care programs: clinical services, service mix, in-kind contributions, indirect costs, and year-to-year expenditures of specific activities. A key lesson is that case studies and pilot testing should be performed before initiating cost analysis to identify underlying variation and to test appropriate methods to adequately control for these differences.     

Censored median regression and profile empirical likelihood

We implement profile empirical likelihood-based inference for censored median regression models. Inference for any specified subvector is carried out by profiling out the nuisance parameters from the “plug-in” empirical likelihood ratio function proposed by Qin and Tsao. To obtain the critical value of the profile empirical likelihood ratio statistic, we first investigate its asymptotic distribution. The limiting distribution is a sum of weighted chi square distributions. Unlike for the full empirical likelihood, however, the derived asymptotic distribution has intractable covariance structure. Therefore, we employ the bootstrap to obtain the critical value, and compare the resulting confidence intervals with the ones obtained through Basawa and Koul’s minimum dispersion statistic. Furthermore, we obtain confidence intervals for the age and treatment effects in a lung cancer data set.