Testing Hypotheses in Nonparametric Models of Production

Data envelopment analysis (DEA) and free disposal hull (FDH) estimators are widely used to estimate efficiency of production. Practitioners use DEA estimators far more frequently than FDH estimators, implicitly assuming that production sets are convex. Moreover, use of the constant returns to scale (CRS) version of the DEA estimator requires an assumption of CRS. Although bootstrap methods have been developed for making inference about the efficiencies of individual units, until now no methods exist for making consistent inference about differences in mean efficiency across groups of producers or for testing hypotheses about model structure such as returns to scale or convexity of the production set. We use central limit theorem results from our previous work to develop additional theoretical results permitting consistent tests of model structure and provide Monte Carlo evidence on the performance of the tests in terms of size and power. In addition, the variable returns to scale version of the DEA estimator is proved to attain the faster convergence rate of the CRS-DEA estimator under CRS. Using a sample of U.S. commercial banks, we test and reject convexity of the production set, calling into question results from numerous banking studies that have imposed convexity assumptions. Supplementary materials for this article are available online.     

Determinants of Portfolio Efficiency Losses in US Self-directed Pension Accounts

This empirical study evaluates the magnitude of efficiency losses of household portfolio choices in self-directed pension accounts (SDAs). It uses data from the Survey of Consumer Finances (SCF). The determinants of the magnitude of efficiency losses across household investors are investigated in detail. The findings of this study lend empirical support to the belief that the magnitude of efficiency losses for household investors differs with the different demographic characteristics and investment propensities. In particular, household investors with long-investment horizons, with more autonomy of choices in their SDAs, or with the tendency to select high levels of portfolio risk in SDAs are more vulnerable to efficiency losses. Factors to predict the levels of portfolio risk maintained by household investors in their SDAs are also explored.     

A constructivist approach to the help-seeking process of clients: A response to cultural diversity

The issue of cultural diversity presents clinicians with both delemmas and opportunities. To deal with such a challenge, I have proposed a constructivist approach to the help-seeking process of clients from diverse ethnoracial backgrounds. A model of clients' help-seeking processes provides a useful and systematic frame for clinicians to understand clients' construction of their problem situations and possible solutions. It provides a useful key for clinicians non-presumptuously to understand clients' subjective experiences, and to enhance clients' ability to resolve problems.     

Voluntarism, self-help and rural community development: Some current approaches

Within the last decade or so, there has developed an increased concern for the welfare of rural communities and for individuals within such communities. At the same time there has emerged a parallel concern for environmental matters, concerned with conservation of species and habitat and the protection of cherished landscapes and amenities. Both sectors of rural concern have been characterised by debate about the means of delivery of policies and programmes in their respective areas and, in particular, about the balance between state action and the activities of the private sector. A common thread running through such debates has been the role of what is loosely called the ‘voluntary sector’, that is the complicated mix of individuals and organisations, local and national, which involve themselves in effort, not for direct payment nor as a routine of work, but because of feelings of commitment, belief and ideology.This paper is concerned with just one aspect of this sector — that which involves social and community aspects of the lives of rural dwellers in the English countryside. Despite this restricted field, there is an attempt to see things within a broader socio-political context, such that rural voluntarism and rural self-help can be assessed not only against a wider picture of volunteering generally but also placed within a political framework, both national and local. Voluntarism and self-help cannot exist independently of the world around them, yet the very process of facing up to the wider political realities creates problems of accountability and control to the extent that some would dismiss the voluntary sector as ineffective at best or the tool of vested interests at worst.     

The cyclical pattern of child physical abuse from a psychoanalytic self-psychology perspective

Child physical abuse is a problem that moves from generation to generation. As yet, there has been no adequate theoretical conceptualization for this phenomenon. This article examines the multigenerational dimension of child abuse from the developmental perspective of psychoanalytic self-psychology. The research data available on the role of empathy in child abuse is integrated into the discussion and applied to the empirical basis of the self-psychology paradigm. Finally, the use of empathy in this theoretical model is applied to a discussion of intervention strategies in a number of treatment modalities.     

Distribution of the cross-correlations of squared residuals in ARIMA models

ABSTRACT The distribution of the cross-correlations of squared residuals from Box-Jenkins models is considered in very general conditions, and the asymptotic distribution is derived. A test for a lagged relationship in volatility for economic time series under instantaneous causality is proposed, and its empirical behaviour is studied. An example involving the international stock market's volatility is studied, and an interesting result is observed.     

Nonparametric regression estimation at design poles and zeros

ABSTRACT In most treatments of nonparametric regression, it is assumed that the marginal density of the explanatory variables is strictly bounded away from zero and infinity. This note investigates the pointwise asymptotics for nonparametric regression when this assumption fails, that is, the marginal density of the explanatory variable has either an isolated zero or a pole at the point of interest.     

NEIGHBOUR ANALYSIS WITH ADJUSTMENT FOR INTERPLOT COMPETITION

In field experiments involving a large number of experimental plots, a neighbour analysis can be used to control environmental variation by estimating the trend within blocks. The effect of interplot competition is another important source of variation which has an influence on the estimation of treatment contrasts. To reduce the effect of the variation from these sources and to improve the precision of comparison between treatments, a spatial model is proposed for incorporating both trend effect and interplot competition. It is a modification to the residual maximum likelihood neighbour analysis of Gleeson & Cullis (1987) using the two neighbouring treatment effects to estimate interplot competition. A real example is used to illustrate this methodology. The results indicate that the extended model gives no appreciable difference in standard error of mean differences compared with the model taking into account the trend effect only. However, the rankings of estimated treatment means do differ. More research using both real and simulated data is required before such models that incorporate trend and competition effects can be confidently recommended.