A monte carlo study of robust estimators of location

Andrews et al (1972) carried out an extensive Monte Carlo study of robust estimators of location. Their conclusions were that the hampel and the skipped estimates, as classes, seemed to be preferable to some of the other currently fashionable estimators. The present study extends this work to include estimators not previously examined. The estimators are compared over short-tailed as well as long-tailed alternatives and also over some dependent data generated by first-order autoregressive schemes. The conclusions of the present study are threefold. First, from our limited study, none of the so-called robust estimators are very efficient over short-tailed situations. More work seems to be necessary in this situation. Second, none of the estimators perform very well in dependent data situations, particularly when the correlation is large and positive. This seems to be a rather pressing problem. Finally, for long-tailed alternatives, the hampel estimators and Hogg-type adaptive versions of the hampels are the strongest classes. The adaptive hampels neither uniformly outperform nor are they outperformed by the hampels. However, the superiority in terms of maximum relative efficiency goes to the adaptive hampels. That is, the adaptive hampels, under their worst performance.     

Analysis of the cross-effects in a cross-lagged panel study

Panel studies are statistical studies in which two or more variables are observed for two or more subjects at two or more points in time. Cross-lagged panel studies are comprised of continuous variables which divide naturally into two sets, and otten the primary statistical issue Is to estimate and test the cross-effects which indicate the degree to which each set is related to the other over time. By taking a regression approach to modeling the relationships, we apply multivariate regression methodology to make inferences about the regression coefficients in a cross-lagged panel model. In particular we develop a test of the hypothesis that the regression coefficients indicating the cross-effects are equal and develop simultaneous confidence bounds for various linear combinations of these regression coefficients.     

A Note on Asymmetry and Robustness in Linear Regression

We discuss the assumption of symmetry in robust linear regression. It is important to distinguish between the intercept term and the slope parameters. Ordinary robust regression requires no assumption of symmetry when interest lies in slope parameters; computer programs, confidence intervals, standard errors, and so forth do not change because the errors are asymmetric. The situation is radically different for bounded-influence estimators. With the exception of the Mallows class, these estimators are inconsistent for slope when the errors are asymmetric.     

Methods for gauging the target populations that community colleges serve

For many community colleges, expanding enrollment demands coincide with shrinking resources, confronting policymakers with multiple competing constituencies of discouraged college-goers. At issue are whether community college enrollments are keeping pace with local growth among the subpopulations that typically attend community colleges; how enrollment levels might differ had participation rates remained unchanged; and which specific population groups, in which subareas of an overall region, are most affected by funding constraints. These issues focus attention on identifying and measuring the diverse populations such colleges serve. We present methods for tracking those populations (1) to gauge how completely (or incompletely) the local community college-going population is enrolling in various campuses, and (2) to delineate the functional service areas of individual campuses. Our methods have applicability to the needs of community college systems generally, especially where the size and geographic distribution of their populations are changing significantly through, for example, immigrant influx and regional expansion. These methods and measures add to the applied demographer’s repertoire of techniques for strengthening local decision-making.     

“Show us what you’ve got”: From experiences of undoing to mobilizing agentic vulnerability in research

This inquiry both builds on and extends exploration into gendered research through a focus on researcher vulnerability and its associated ethics. We discuss six critical vignettes across Western and Eastern contexts in which female researchers are “undone” and subsequently “redone” during their research endeavors. We draw upon Butler's work on gender and vulnerability, theorized as a subset of precarity. Attention is drawn to attempts to reframe, understand, and mobilize vulnerability differently, as a form of resistance, research activism, and emancipatory enactment. We propose agentic vulnerability as speaking to felt moments of vulnerability experienced in field research. We extend this contribution into a theorization of the researcher as activist, outlining practical applications of this concept. Ultimately, we seek to reposition agentic vulnerability in institutional research as a source of new ethics, research practices, and activism.     

Indefinite terminating points and the iterated Prisoner's Dilemma

Conclusion In conclusion, I shall indicate one consequence of (3.4). The major resultof work on infinitely iterated Prisoner's Dilemma games is that there existcooperative equilibria in such games. I have suggested above that myaccount of finitely, but indefinitely, iterated Prisoner's Dilemma gamesreflects the nature of genuine iterated Prisoner's Dilemmas more accu-rately than accounts involving infinite iterations. If my suggestion iscorrect, then one consequence of (3.4) - of there being only uncooperativeequilibria in finitely, but indefinitely, iterated games - is to call intoquestion the significance of the existence of cooperative equilibria ininfinitely iterated Prisoner's Dilemma games.Thanks to Jules Coleman, Mark Isaac, John Pollock, and Gregory Karva for helpful comments on earlier versions of this paper. Some of these results were presented as part of similar papers given at the 1986 meeting of the society for Exact Philosophy and at Bowling Green University.     

Coming to Terms with Termination of Public Organizations

Why do some public organizations survive and others do not? The bureaucratic retrenchment efforts since the 1980s showed public administration scholars that the structure of the state has its own demography. Yet studies on the survival of public organizations tested different hypotheses using different methods and definitions. This review article reflects on the consequences of different takes on termination, it compares and reports on the main findings thus far and argues that we should study organizational survival focusing on transitions to build on existing empirical work.     

Emotion Situation Knowledge in Elementary School: Models of Longitudinal Growth and Preschool Correlates

We examined individual differences in developmental trajectories of emotion situation knowledge (ESK), at three time points throughout elementary school in a sample of children from economically disadvantaged families. Results showed that ESK and the subscales of joy, fear, anger, shame and interest exhibited positive growth from the first to the fifth grade, whereas scores on the sad subscale declined slightly. Preschool verbal ability predicted first grade scores for joy, fear, and anger, and growth in scores for shame across time. Preschool negative emotional intensity predicted slower growth in overall ESK and the anger and shame subscales. Taken together, these results broaden our basic knowledge of how children's use of situational cues to infer others' emotions develops in middle and late childhood.