Tailor-made tests for goodness of fit to semiparametric hypotheses

We introduce a new framework for constructing tests of general semiparametric hypotheses which have nontrivial power on the $n^{-1/2}$ scale in every direction, and can be tailored to put substantial power on alternatives of importance. The approach is based on combining test statistics based on stochastic processes of score statistics with bootstrap critical values.Comment: Published at http://dx.doi.org/10.1214/009053606000000137 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Eleven Years of Data on the Jefferson Scale of Empathy-Medical Student Version (JSE-S): Proxy Norm Data and Tentative Cutoff Scores.

OBJECTIVE: This study was designed to provide typical descriptive statistics, score distributions and percentile ranks of the Jefferson Scale of Empathy-Medical Student version (JSE-S) of male and female medical school matriculants to serve as proxy norm data and tentative cutoff scores. SUBJECTS AND METHODS: The participants were 2,637 students (1,336 women and 1,301 men) who matriculated at Sidney Kimmel (formerly Jefferson) Medical College between 2002 and 2012, and completed the JSE at the beginning of medical school. Information extracted from descriptive statistics, score distributions and percentile ranks for male and female matriculants were used to develop proxy norm data and tentative cutoff scores. RESULTS: The score distributions of the JSE tended to be moderately skewed and platykurtic. Women obtained a significantly higher mean score (116.2 ± 9.7) than men (112.3 ± 10.8) on the JSE-S (t2,635 = 9.9, p \u3c 0.01). It was suggested that percentile ranks can be used as proxy norm data. The tentative cutoff score to identify low scorers was ≤ 95 for men and ≤ 100 for women. CONCLUSIONS: Our findings provide norm data and cutoff scores for admission decisions under certain conditions and for identifying students in need of enhancing their empathy

Score, Pseudo-Score and Residual Diagnostics for Spatial Point Process Models

We develop new tools for formal inference and informal model validation in the analysis of spatial point pattern data. The score test is generalized to a "pseudo-score" test derived from Besag's pseudo-likelihood, and to a class of diagnostics based on point process residuals. The results lend theoretical support to the established practice of using functional summary statistics, such as Ripley's $K$-function, when testing for complete spatial randomness; and they provide new tools such as the compensator of the $K$-function for testing other fitted models. The results also support localization methods such as the scan statistic and smoothed residual plots. Software for computing the diagnostics is provided.Comment: Published in at http://dx.doi.org/10.1214/11-STS367 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Power of edge exclusion tests in graphical gaussian models

Asymptotic multivariate normal approximations to the joint distributions of edge exclusion test statistics for saturated graphical Gaussian models are derived. Non-signed and signed square-root versions of the likelihood ratio, Wald and score test statistics are considered. Non-central chi-squared approximations are also considered for the non-signed versions. These approximations are used to estimate the power of edge exclusion tests and an example is presented.<br/

Change-point model on nonhomogeneous Poisson processes with application in copy number profiling by next-generation DNA sequencing

We propose a flexible change-point model for inhomogeneous Poisson Processes, which arise naturally from next-generation DNA sequencing, and derive score and generalized likelihood statistics for shifts in intensity functions. We construct a modified Bayesian information criterion (mBIC) to guide model selection, and point-wise approximate Bayesian confidence intervals for assessing the confidence in the segmentation. The model is applied to DNA Copy Number profiling with sequencing data and evaluated on simulated spike-in and real data sets.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS517 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Small-sample corrections for score tests in Birnbaum-Saunders regressions

In this paper we deal with the issue of performing accurate small-sample inference in the Birnbaum-Saunders regression model, which can be useful for modeling lifetime or reliability data. We derive a Bartlett-type correction for the score test and numerically compare the corrected test with the usual score test, the likelihood ratio test and its Bartlett-corrected version. Our simulation results suggest that the corrected test we propose is more reliable than the other tests.Comment: To appear in the Communications in Statistics - Theory and Methods, http://www.informaworld.com/smpp/title~content=t71359723

Assessing the impact of the introduction of the World Health Organization growth standards and weight-for-height z-score criterion on the response to treatment of severe acute malnutrition in children: Secondary data analysis

OBJECTIVE: The objective of our study was to assess the impact of adopting the World Health Organization growth standards and weight-for-height z-score criterion on the response to treatment of severe acute malnutrition in children compared with the use of the National Center for Health Statistics growth reference. METHODS: We used data from children aged 6 to 59 months with acute malnutrition who were admitted to the Médecins sans Frontières nutrition program in Maradi, Niger, during 2006 (N = 56214). Differences in weight gain, duration of treatment, recovery from malnutrition, mortality, loss to follow-up, and need for inpatient care were compared for severely malnourished children identified according to the National Center for Health Statistics reference and weight-for-height <70% of the median criterion versus the World Health Organization standards and the weight-for-height less than -3 z-score criterion. RESULTS: A total of 8 times more children (n = 25754) were classified as severely malnourished according to the World Health Organization standards compared with the National Center for Health Statistics reference (n = 2989). Children included according to the World Health Organization standards had shorter durations of treatment, greater rates of recovery, fewer deaths, and less loss to follow-up or need for inpatient care. CONCLUSIONS: The introduction of the World Health Organization standards with the z-score criterion to identify children for admission into severe acute malnutrition treatment programs would imply the inclusion of children who are younger but have relatively higher weight for height on admission compared with the National Center for Health Statistics reference. These children have fewer medical complications requiring inpatient care and are more likely to experience shorter durations of treatment and lower mortality rates. The World Health Organization standards with the z-score criterion might become a useful tool for the early detection of acute malnutrition in children, although additional research on the resource implications of this transition is required