The pitman nearness criterion and its determination

A general method for determining Pitman Nearness is given In the case of univariate estimators. This method is then applied to some estimation problems. The concept of Pitman Nearness is also generalized to the multivariate case. The James-Stein estimators are used to illustrate the multivariate comparison.     

Simple inference in multinomial and ordered logit

This paper provides some simple methods of interpreting the coefficients in multinomial logit and ordered logit models. These methods are summarized in Propositions concerning the magnitudes, signs, and patterns of partial derivatives of the outcome probabilities with respect to the exogenousvariables. The paper also provides an empirical example illustrating the use of these Propositions.     

Adding functions to ensure regression converges

Regression fits a curve to data by minimizing a function of the residuals. The process of fitting a family of functions may fail to converge because the family of candidate functions has no minimum. After investigating what functions to add to a family to ensure a minimum exists, four families are examined. The family of polynomials needs no additional functions. Additional functions are found for the families of exponential growth curves, probit curves, and logistic curves. A sufficient condition tells when the minimum is not in the original family.     

Posture Development in Infants at Heightened versus Low Risk for Autism Spectrum Disorders

Evidence suggests that children and adults diagnosed with autism spectrum disorders (ASD) exhibit difficulties with postural control. Retrospective video studies of infants later diagnosed with ASD indicate that infants who eventually receive an ASD diagnosis exhibit delays in postural development. This study investigates early posture development prospectively and longitudinally in 22 infants at heightened biological risk for ASD (HR) and 18 infants with no such risk (Low Risk; LR). Four HR infants received an autism diagnosis (AD infants) at 36 months. Infants were videotaped at home at 6, 9, 12, and 14 months during everyday activities and play. All infant postures were coded and classified as to whether or not they were infant‐initiated. Relative to LR infants, HR infants were slower to develop skill in sitting and standing postures. AD infants exhibited substantial delays in the emergence of more advanced postures and initiated fewer posture changes. Because posture advances create opportunities for infants to interact with objects and people in new and progressively more sophisticated ways, postural delays may have cascading effects on opportunities for infant exploration and learning. These effects may be greater for infants with ASD, for whom posture delays are more significant.     

Response transformations in repeated measures and growth curve models

This article describes estimation and inference procedures for the parameters of the Box-Cox and foided-power transformations in repeated measures and growth curve models. Procedures for computing maximum likelihood estimates of the transformation and covariance parameters under several covanance structures (omnibus sphericity, local sphericity, and unstructured) are described. Lack of fit statistics and hypothesis tests for comparing these structures also are described. The procedures are illustrated on three data sets. Software for performing the analyses in the SAS System is described and is available from the authors.     

Perceptions of efficacy in the use of contemporary film in social work education: An exploratory study

This article discusses the use of contemporary film in social work education, including the theoretical rationale for the inclusion of film from the perspective of narrative and adult learning theory as well as the application of the case method to the use of film. The student viewpoint and perspective is provided through the results of an exploratory research study with 109 Baccalaureate social work students who completed a survey questionnaire following a classroom activity involving a contemporary film. Analysis of the quantitative data and qualitative comments indicates that students believe that film is a beneficial adjunct to textbook and lecture content.     

Social interactions and the salience of social identity

We explore the effect of identity salience on behaviour in a simple social interaction. Specifically, we compare ultimatum bargaining across three treatments: priming subjects with a shared identity, priming subjects with an identity distinct from those with whom they will interact, and priming subjects with no particular identity. We find that subjects are most cooperative in the identity-priming treatment and least cooperative in the distinctiveness-priming treatment. Similarly, subjects reveal the highest demands in the identity-priming treatment and the lowest demands in the distinctiveness-priming treatment. We discuss the implications of these results with respect to the literature on organizational identity.