Recovered errors and normal diagnostics in regression

Diagnostics for normal errors in regression typically utilize ordinary residuals, despite the failure of assumptions to validate their use. Case studies here show that such misuse may be critical. A remedy invokes recovered errors having the required properties, taking into account that such errors are closer to normality than are disturbances in the observations themselves. Simulation studies show consistent improvement over the usual methods in small samples. In addition, effects on normal diagnostics due to various model violations are examined. Received: January 1999     

Bayesian geoadditive modelling of breastfeeding initiation in Nigeria

A study into the geographical variability of timing of initial child breastfeeding after birth was carried out with the data set from the 1999 Nigeria Demographic and Health Survey. The effect of the metrical covariate of the mother's age at birth was assumed to be nonlinear and estimated nonparametrically. Other categorical covariates are estimated in the usual parametric form. Within a Bayesian context, appropriate priors are assigned for the geographical location, vector of the unknown (nonlinear) smooth functions and a further vector of the fixed effect parameters. For instance, a Markov random field prior is assumed on the spatial effects. Inferences are based on Markov chain Monte Carlo techniques while Bayesian model diagnostics are based on the deviance information criteria. Copyright © 2004 John Wiley & Sons, Ltd.     

Diagnostics analysis for log‐Birnbaum–Saunders regression models with censored data

This article develops influence diagnostics for log‐Birnbaum–Saunders (LBS) regression models with censored data based on case‐deletion model (CDM). The one‐step approximations of the estimates in CDM are given and case‐deletion measures are obtained. Meanwhile, it is shown that CDM is equivalent to mean shift outlier model (MSOM) in LBS regression models and an outlier test is presented based on MSOM. Furthermore, we discuss a score test for homogeneity of shape parameter in LBS regression models. Two numerical examples are given to illustrate our methodology and the properties of score test statistic are investigated through Monte Carlo simulations under different censoring percentages.     

Straight-line models in star-shaped mixtures

Normal-theory inferences are validated in part for straight-line models having star-contoured errors. Adverse effects for the intercept include inconsistent estimation and disturbances in levels of the standard tests. Tests for slope remain exact in level; they are unbiased; and their power through mixing typically dominates the standard Gaussian case. Bounds on level, and envelopes for power curves, are given for certain ensembles and mixtures of distributions, and these are evaluated numerically for selected cases. Effects of mixtures on model diagnostics are examined further.     

Using data envelopment analysis to quantify ILO objectives and identify policies conducive to decent work in a globalizing world

The International Labor Office, an arm of the UN based in Geneva, has as its goal the promotion of opportunities for women and men to obtain decent and productive work, in conditions of freedom, equity, security and human dignity. Since 1999, the ILO has conducted a series of studies of decent work. In 2001, the organization posed the global challenge of reducing the decent work deficit as measured by an employment gap, rights gap, a social protection gap, and a social dialogue gap. Using standard economic terms, “decent work” may be seen as an efficiency point along a generalized input-output function, dependent upon variables of both economic performance and economic and social policy. The decent work deficit of a given country (if any) is then obtained as the difference between an observed point and its projection on the efficiency frontier. Using data envelopment analysis (DEA), we fit a piecewise linear frontier to observations for 61 countries from all continents. Importantly, 27 of these countries lie on the decent work frontier; the remaining ones reveal conditions of decent work deficit. The possibilities of reducing such deficits by appropriate control of policy variables are discussed.     

Hodges–Lehmann Detection of Structural Shocks – An Analysis of Macroeconomic Dynamics in the Euro Area

Structural shocks in multivariate dynamic systems are hidden and often identified with reference to a priori economic reasoning. Based on a non‐Gaussian framework of independent shocks, this work provides an approach to discriminate between alternative identifying assumptions on the basis of dependence diagnostics. Relying on principles of Hodges–Lehmann estimation, we suggest a decomposition of reduced form covariance matrices that yields implied least dependent (structural) shocks. A Monte Carlo study underlines the discriminatory strength of the proposed identification strategy. Applying the approach to a stylized model of the Euro Area economy, independent shocks conform with features of demand, supply and monetary policy shocks.     

Strategyproof multiple assignment using quotas

The allocation of heterogeneous and indivisible objects is considered where there is no medium of exchange. We characterize the set of strategyproof, nonbossy, Pareto-optimal, and neutral social choice functions when preferences are monotonic and quantity-monotonic. The characterized sets of social choice functions are sequential; agents are assigned their favorite objects among the objects not given to others before them, subject to a quota. Received: 5 January 1999 / Accepted: 14 June 1999     

Distortion in statistical inference: the distinction between data contamination and model deviation

The present work develops a basic classification scheme for distortion in the framework of classical statistical inference. In particular, it emphasizes the still outstanding and consequent distinction between data contamination and model deviation. It is explored when different implications on the performance of statistical inference procedures under the two types of distortion are possible and how these can be detected. A critical review of some important approaches in the robustness and diagnostics literature finally indicates which of them is aimed at data contamination and which at model deviation (independently from what has been claimed originally). The paper raises awareness of the above problem through a constructive discussion – it is not meant to introduce new methodology     

Characterizations of the Pareto and related distributions

In this note, a class of Pareto distributions is characterized based on the Shannon entropy of k-record statistics. As a consequence of that characterizations of the uniform and exponential distributions are given. Received: October 1999     

Identifying interdependent behaviour in an empirical model of labour supply

In this paper we test a particular form of interdependent behaviour, namely the hypothesis that individuals' choices of hours of work are influenced by the average hours of work in a social reference group. There are problems in empirically disentangling the effects of interdependent behaviour and preference variation across groups. We show that panel data or data from several points in time are needed. In the empirical analysis we combine cross-section data from 1973, 1980, and 1990. Our results support the hypothesis of interdependent behaviour. The implication is that conventional tax policy predictions, in which preference interdependencies are neglected, will tend to underestimate the effect of a tax reform on hours of work. Our point estimates suggest that conventional calculations would capture only about a third of the actual change in hours of work. Copyright © 1999 John Wiley & Sons, Ltd.     

Volunteering: the long arm of the law

Voluntary organisations are beginning to acknowledge that they have responsibilities towards volunteers that closely resemble their duties towards paid staff. There is a move towards interviewing volunteers, taking up references and defining the terms and conditions of volunteer work. This paper explores some legal implications of the formalisation of the relationship between voluntary organisations and their voluntary workers. Particular emphasis is placed on the problems that can arise when voluntary workers receive payment over and above the reimbursement of their actual expenditure. Copyright © 1999 Henry Stewart Publications     

The fundraising database audit

The concept of the database audit is relatively new, both in commercial and in nonprofit marketing. This paper sets out the case, benefits, pitfalls and techniques that are part of database auditing. The principles of database auditing are explained, with measurement, comparison, retrospection, trends, top-down, KPIs, diagnostics and other key concepts explored. A typical audit sequence is shown. The benefits of auditing are described, and several supporting tables and chart examples from real charity audits given, including lifetime value, growth and attrition of a database and active/inactive supporter cohorts. The challenges and difficulties experienced in auditing are described, and software tools illustrated. Common pitfalls are described and the future of database audits is predicted.     

Influence measures on profile analysis with elliptical data through Frèchet’s metric

In this paper, from Frèchet’s metric, diagnostic tools are constructed for the detection of influential observations in Profile Analysis with elliptically distributed random errors . This distributional hypothesis allows the application of the proposed diagnostics to a wide variety of random experiences, not only for data from a multivariate normal distribution but also from other symmetric distributions, commonly used in studies of several sciences. The diagnostics are based on Frèchet’s distance between the distributions of the basic statistics in Profile Analysis, in the postulated model and in the perturbed model obtained by deleting an observation from the sample data. This metric is highly useful since it enables the analysis of the influence on the point estimation and the estimation error. Applications on two data sets are provided.     

On optimal regulation of price and R&D with asymmetric information

This paper deals with the optimal regulation for cost-reducing R&D and pricing in natural monopoly that is privately informed on its efficiency. We extend the work of Cantner and Kuhn (Rev Econ Des 4:191–204, 1999) and then we are able to analyse the entire effects of the interplay between agent’s efficiency and investment in R&D particularly considering the substitutability case.     

对监理在建筑施工阶段的质量控制措施的探讨研究

本文对我国建筑工程监理的现状进行了分析同时提出建议,并对建筑施工过程中如何做好质量形成的五个要素的监理工作提出了措施,对监理在建筑施工阶段的工作提出了方法。     

Local influence analysis for Poisson autoregression with an application to stock transaction data

In statistical diagnostics and sensitivity analysis, the local influence method plays an important role and has certain advantages over other methods in several situations. In this paper, we use this method to study time series of count data when employing a Poisson autoregressive model. We consider case‐weights, scale, data, and additive perturbation schemes to obtain their corresponding vectors and matrices of derivatives for the measures of slope and normal curvatures. Based on the curvature diagnostics, we take a stepwise local influence approach to deal with data with possible masking effects. Finally, our established results are illustrated to be effective by analyzing a stock transactions data set.     

The future of work and family: Critical trends for policy,practice, and research

Work/life “thought leaders” from 28 large corporations carried out an environmental scanning process with the objective of linking work/life policies and practices to critical business and environmental trends. Globalization, technological change, and organizational flexibility are trends that have been commonly identified in other environmental scanning efforts, but their relationship to work/life issues has often been ignored. Similarly, the relationship of changing family structures to business goals has not received the attention it deserves. Through this linking process, work/life advocates can demonstrate the value of their efforts to other corporate decision makers. Innovative corporate work/life initiatives that are responsive to these important trends are described. © 1999 John Wiley & Sons, Inc.     

Assessing the presence of harmful collinearity and other forms of weak data through a test for signal-to-noise

Data weaknesses (such as collinearity) reduce the quality of least-squares estimates by inflating parameter variances. Standard regression diagnostics and statistical tests of hypothesis are unable to indicate such variance inflation and hence cannot detect data weaknesses. In this paper, then, we consider a different means for determining the presence of weak data based on a test for signal-to-noise in which the size of the parameter variance (noise) is assessed relative to the magnitude of the parameter (signal). This test is combined with other collinearity diagnostics to provide a test for the presence of harmful collinearity and/or short data. The entire procedure is illustrated with an equation from the Michigan Quarterly Econometric Model. Tables of critical values for the test are provided in an appendix.     

The impact of the National Minimum Wage in low‐wage sectors: does the Earnings Top‐up Evaluation study add to our understanding?

Recent work investigating the possible impact of the introduction of the UK National Minimum Wage (NMW) in April 1999 has focused on the analysis of care homes, a sector particularly associated with low‐wage employment. In this article we attempt to add to these findings by utilising the Earnings Top‐up Evaluation (ETUE) survey which was carried out in 1996, 1997 and 1999, and aimed to over‐sample establishments operating in low‐wage sectors. Initially, we utilise the panel element of the ETUE to carry out a similar analysis to that adopted for the care homes data. However, in addition to this ‘establishment‐level’ analysis, we also utilise information on wages and employment in three non‐managerial skill groups, within this panel of establishments, to carry out an analysis at the level of the skill group. In this second set of analyses we are able to reject the null hypotheses of parameter insignificance, identifying a negative employment effect of the 1999 NMW, although this is only true of one of our indicators of NMW impact and its magnitude is small. In the conclusion to the article, we discuss our results in light of the findings from other similar studies.     

Turn to the material: Remote diagnostics systems and new forms of boundary-spanning

To learn and adapt, organizations engage widely in Information Technology (IT)-mediated boundary-spanning. This involves making sense of a swath of peripheral information made available by digital means so as to expand local knowledge. Prior research on boundary-spanning has paid scant attention to material differences between IT systems in enabling or constraining such activity. In this article, we argue that material features do matter: features afforded by IT systems have a significant impact on the form and content of boundary-spanning. We analyze material features and related affordances provided by remote diagnostics systems – a family of ubiquitous IT systems. These features allow remote diagnostics systems to collect, store, and continuously analyze data about the state of machinery and related production processes across space, time and organizational boundaries. Organizations use these systems to determine when maintenance intervention is needed, or to improve their production processes. Often, these systems are run by external service providers at remote sites, which become the new ears and the eyes of a focal organization’s production processes. Building on a longitudinal multi-site case study of two organizations, we explore the impacts of remote diagnostics systems on boundary-spanning. We observe that material features afforded by the remote diagnostics led the organizations to change their boundary-spanning in contradictory ways. On one hand, they reinforced existing boundaries. On the other hand, they crossed or cut down others, or created new ones. This suggests that the material features of these systems, when combined with new knowledge creation and sharing practices, within and between the local and the remote sites generate richer, multi-faceted inter-organizational knowledge flows. We surmise that IT’s new material features will continue to significantly shape organizing logics that determine where and when organizational boundaries are drawn and crossed. Future boundary-spanning will increasingly be shaped by socio-technical assemblages brought together by increasingly pervasive IT capabilities.