On Non-parametric Estimation of the Survival Function with Competing Risks

The non-parametric maximum likelihood estimators (MLEs) are derived for survival functions associated with individual risks or system components in a reliability framework. Lifetimes are observed for systems that contain one or more of those components. Analogous to a competing risks model, the system is assumed to fail upon the first instance of any component failure; i.e. the system is configured in series. For any given risk or component type, the asymptotic distribution is shown to depend explicitly on the unknown survival function of the other risks, as well as the censoring distribution. Survival functions with increasing failure rate are investigated as a special case. The order restricted MLE is shown to be consistent under mild assumptions of the underlying component lifetime distributions.     

Bayesian estimation for the Pareto income distribution

The Bayes estimators of the Gini index, the mean income and the proportion of the population living below a prescribed income level are obtained in this paper on the basis of censored income data from a pareto income distribution. The said estimators are obtained under the assumptions of a two-parameter exponential prior distribution and the usual squared error loss function. This work is also extended to the case when the income data are grouped and the exact incomes for the individuals in the population are not available. The method for the assessment of the hyperparameters is also outlined. Finally, the results are generalized for the doubly truncated gamma prior distribution. Now deceased.     

Rape Jokes

A curated selection of rape jokes taken from various Anglophone websites devoted to crowd-sourced offensive humor. Individual jokes may have been slightly modified to emphasize their poetic features.     

Bidirectional Linkages Between Emotion Recognition and Problem Behaviors in Elementary School Children

Cross-sectional studies support negative associations between children’s skills in recognizing emotional expressions and their problem behaviors. Few studies have examined these associations over time, however, precluding our understanding of the direction of effects. Emotion recognition difficulties may contribute to the development of problem behaviors; additionally, problem behaviors may constrain the development of emotion recognition skill. The present study tested the bidirectional linkages between children’s emotion recognition and teacher-reported problem behaviors in 1st and 3rd grade. Specifically, emotion recognition, hyperactivity, internalizing behaviors, and externalizing behaviors were assessed in 117 children in 1st grade and in 3rd grade. Results from fully cross-lagged path models revealed divergent developmental patterns: Controlling for concurrent levels of problem behaviors and first-grade receptive language skills, lower emotion recognition in 1st grade significantly predicted greater internalizing behaviors, but not hyperactivity or externalizing behaviors, in 3rd grade. Moreover, greater hyperactivity in 1st grade marginally predicted lower emotion recognition in 3rd grade, but internalizing and externalizing behaviors were not predictive of emotion recognition over time. Together, these findings extend previous research to identify specific developmental pathways, whereby emotion recognition difficulties contribute to the development of internalizing behaviors, and early hyperactivity may contribute to the development of emotion recognition difficulties, thus highlighting the importance of examining these processes and their mutual development over time.     

Workers’ Remittances to India: An Examination of Transfer Cost and Efficiency

Regarding the time efficiency of remittance transfer channels to India, the evidence suggests that traditional banking instruments are relatively inefficient as compared to the new information technology‐enabled products. Transfer arrangement of the Indian banks with overseas exchange houses has reduced the settlement cycle and the cost. Both the banks and money transfer operators (MTOs) are able to keep the transaction cycle low through the use of information technology‐enabled formats. Given that the average cost curve of the banks is located to the right of the average cost curve of the MTOs, greater potential exists for the improvement in overall efficiency of the two entities, particularly through the sharing of messaging and the access and disbursement networks to reduce the overhead cost. The estimates of error correction model reveal that the transaction fee and payment infrastructure are significant determinants of remittance flows, underscoring the scope of policy measures in influencing remittance inflows. The estimates indicate that over the medium to long‐term horizon, transaction cost emerges as the most dominant variable explaining the variation in remittances. The payments infrastructure also explains about 10 per cent variation in remittances over the medium‐term. The impulse response analysis further reveals that the favourable shocks to transaction fees and the payments infrastructure cause steady improvement in remittance inflows over the medium‐term horizon, thus underlining the importance of cost and efficiency in affecting the workers’ remittances.     

Testing the validity of social capital measures in the study of information and communication technologies

Social capital has been considered a cause and consequence of various uses of new information and communication technologies (ICTs). However, there is a growing divergence between how social capital is commonly measured in the study of ICTs and how it is measured in other fields. This departure raises questions about the validity of some of the most widely cited studies of social capital and ICTs. We compare the Internet Social Capital Scales (ISCS) developed by Williams [2006. On and off the ’net: scales for social capital in an online era. Journal of Computer-Mediated Communication, 11(2), 593–628. doi: 10.1111/j.1083-6101.2006.00029.x] – a series of psychometric scales commonly used to measure ‘social capital’ – to established, structural measures of social capital: name, position, and resource generators. Based on a survey of 880 undergraduate students (the population to which the ISCS has been most frequently administered), we find that, unlike structural measures, the ISCS does not distinguish between the distinct constructs of bonding and bridging social capital. The ISCS does not have convergent validity with structural measures of bonding or bridging social capital; it does not measure the same concept as structural measures. The ISCS conflates social capital with the related constructs of social support and attachment. The ISCS does not measure perceived or actual social capital. These findings raise concerns about the interpretations of existing studies of ‘social capital’ and ICTs that are based on the ISCS. Given the absence of measurement validity, we urge those studying social capital to abandon the ISCS in favor of alternative approaches.     

Identification of composite (∑+II) arma models by relatively simpler models

In the real world situations, many time series are aggregates of two or more time series. An aggregation may take place due to an addition or the product or both of two or more time series. We are often interested in the study of the properties of aggregates which are, in turn, dependent on the properties of the constituent series. Motivated by this problem, the authors study in this paper the properties of models generated by the operator (Σ+II) on autoregressive-moving-average (ARMA) processes of orders (p_i,q_i), i = l→n . A few practical examples where such models have been used are given in the introduction and an illustrative numerical example is discussed at the end of the paper.