Sampling design proportional to order statistic of auxiliary variable

The sampling designs dependent on sample moments of auxiliary variables are well known. Lahiri (Bull Int Stat Inst 33:133–140, 1951) considered a sampling design proportionate to a sample mean of an auxiliary variable. Sing and Srivastava (Biometrika 67(1):205–209, 1980) proposed the sampling design proportionate to a sample variance while Wywiał (J Indian Stat Assoc 37:73–87, 1999) a sampling design proportionate to a sample generalized variance of auxiliary variables. Some other sampling designs dependent on moments of an auxiliary variable were considered e.g. in Wywiał (Some contributions to multivariate methods in, survey sampling. Katowice University of Economics, Katowice, 2003a); Stat Transit 4(5):779–798, 2000) where accuracy of some sampling strategies were compared, too.These sampling designs cannot be useful in the case when there are some censored observations of the auxiliary variable. Moreover, they can be much too sensitive to outliers observations. In these cases the sampling design proportionate to the order statistic of an auxiliary variable can be more useful. That is why such an unequal probability sampling design is proposed here. Its particular cases as well as its conditional version are considered, too. The sampling scheme implementing this sampling design is proposed. The inclusion probabilities of the first and second orders were evaluated. The well known Horvitz–Thompson estimator is taken into account. A ratio estimator dependent on an order statistic is constructed. It is similar to the well known ratio estimator based on the population and sample means. Moreover, it is an unbiased estimator of the population mean when the sample is drawn according to the proposed sampling design dependent on the appropriate order statistic.     

Adaptive Build-up and Breakdown of Trust: An Agent Based Computational Approach

This article employs Agent-Based Computational Economics (ACE) to investigate whether, and under what conditions, trust is viable in markets. The emergence and breakdown of trust is modeled in a context of multiple buyers and suppliers. Agents develop trust in a partner as a function of observed loyalty. They select partners on the basis of their trust in the partner and potential profit, with adaptive weights. On the basis of realized profits, they adapt the weight they attach to trust relative to profitability, and their own trustworthiness, modeled as a threshold of defection. Trust and loyalty turn out to be viable under fairly general conditions.     

In Search of ‘Managerial Work’: Past,Present and Future of an Analytical Category

Based on a comprehensive review of literature, the paper examines how ‘managerial work’ as a fluid analytical category has been approached methodologically, theoretically and empirically for more than 60 years. In particular, it highlights the existence of competing scholarly understandings regarding its nature, performance, meaning and politics. The authors suggest that subsequent empirical investigations have too often worked, methodologically and theoretically, to slot in, and thus effectively reduce, the term to a particular pre‐existing box, rather than exploring open‐endedly the what and how, but also the why of ‘managerial work’ as a distinct mode of situated ordering. Having represented the concept's past and present by identifying four distinct research approaches reflected in representative publications, the authors suggest that more attention should be devoted to a mode of analytical departure that promises to address directly the suggested shortcomings in the literature. Specifically, it is argued that much could be gained if contemporary notions of practice were brought into the study of managerial work. To this end, the authors outline the contours of a practice‐based approach as a sensitizing framework for understanding managerial work by highlighting the situated, relational, sociomaterial, meaning‐making and consequence‐oriented analytical foci the approach suggests, and suggesting a number of conjoint research questions, as well as acknowledging subsequent limitations.     

Discriminant coordinates analysis for multivariate functional data

Abstract

One of the basic statistical methods of dimensionality reduction is analysis of discriminant coordinates given by Fisher (1936 Fisher, R. A. 1936. The use of multiple measurements in taxonomic problem. Annals of Eugenics 7 (2):179–88. doi:10.1111/j.1469-1809.1936.tb02137.x.[Crossref] , [Google Scholar]) and Rao (1948). The space of discriminant coordinates is a space convenient for presenting multidimensional data originating from multiple groups and for the use of various classification methods (methods of discriminant analysis). In the present paper, we adapt the classical discriminant coordinates analysis to multivariate functional data. The theory has been applied to analysis of textural properties of apples of six varieties, measured over a period of 180?days, stored in two types of refrigeration chamber.     

Trust in American Government: Longitudinal Measurement Equivalence in the ANES, 1964–2008

For over 50 years (1958–2012) the American National Election Studies (ANES) survey has been measuring citizens’ evaluations of the trustworthiness of the “government in Washington”—an indicator that has been widely used to monitor the dynamics of political trust in the US over time. However, a critical assumption in using attitudinal constructs for longitudinal research is that the meaning-and-interpretation of such items should be comparable across groups of respondents at any one point in time and across samples over time. Using multigroup confirmatory factor analysis for ordered-categorical data, we test the measurement equivalence assumption with data collected by the ANES from 1964 to 2008. The results confirm that the ANES’ political trust scale has the same basic factorial structure over time. But for two key items, several threshold parameters were found to be different across time points, indicating that the meaning-and-interpretation of these questions, and especially the question about whether the government in Washington wastes money that people pay in taxes, varies significantly over time.

     

Letter to the Editor: Respecting the Plurality of Value and the Messiness of Scientific Practice

Evaluations of authorship and recommendations for authorship policies best heed the plurality of valuation cultures that traverse scientific practices and respect the messiness of scientific practices, for those are reflected in authorship and authorship sequence decisions.     

An Automatic Test for the Umbrella Alternatives

The paper proposes a new test for detecting the umbrella pattern under a general non‐parametric scheme. The alternative asserts that the umbrella ordering holds while the hypothesis is its complement. The main focus is put on controlling the power function of the test outside the alternative. As a result, the asymptotic error of the first kind of the constructed solution is smaller than or equal to the fixed significance level α on the whole set where the umbrella ordering does not hold. Also, under finite sample sizes, this error is controlled to a satisfactory extent. A simulation study shows, among other things, that the new test improves upon the solution widely recommended in the literature of the subject. A routine, written in R, is attached as the Supporting Information file.     

Macro-Economic Factors in Credit Risk Calculations: Including Time-Varying Covariates in Mixture Cure Models

The prediction of the time of default in a credit risk setting via survival analysis needs to take a high censoring rate into account. This rate is because default does not occur for the majority of debtors. Mixture cure models allow the part of the loan population that is unsusceptible to default to be modeled, distinct from time of default for the susceptible population. In this article, we extend the mixture cure model to include time-varying covariates. We illustrate the method via simulations and by incorporating macro-economic factors as predictors for an actual bank dataset.     

New bounds for locally irregular chromatic index of bipartite and subcubic graphs

A graph is locally irregular if the neighbors of every vertex v have degrees distinct from the degree of v. A locally irregular edge-coloring of a graph G is an (improper) edge-coloring such that the graph induced on the edges of any color class is locally irregular. It is conjectured that three colors suffice for a locally irregular edge-coloring. In the paper, we develop a method using which we prove four colors are enough for a locally irregular edge-coloring of any subcubic graph admiting such a coloring. We believe that our method can be further extended to prove the tight bound of three colors for such graphs. Furthermore, using a combination of existing results, we present an improvement of the bounds for bipartite graphs and general graphs, setting the best upper bounds to 7 and 220, respectively.