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The assumption of strongly ignorable treatment assignment is required for eliminating selection bias in observational studies. To meet this assumption, researchers often rely on a strategy of selecting covariates that they think will control for selection bias. Theory indicates that the most important covariates are those highly correlated with both the(More)
Propensity score analysis is a relatively recent statistical innovation that is useful in the analysis of data from quasi-experiments. The goal of propensity score analysis is to balance two non-equivalent groups on observed covariates to get more accurate estimates of the effects of a treatment on which the two groups differ. This article presents a(More)
OBJECTIVE School- and community-based alcohol prevention programs are often evaluated using a group-randomized trial (GRT) design with a single pretest and a single posttest survey. To size such studies properly, investigators need accurate estimates of the variance and intraclass correlation that will be operative in their analyses. Until recently, the(More)
The purpose of this study was to assess and determine content knowledge of National Collegiate Athletic Association Strength and Conditioning Coaches (SCCs) regarding prevention and recognition of exertional heat stroke (EHS) and to determine whether the type of professional certification is an indicator of enhanced content knowledge. A questionnaire was(More)
Acknowledgments We thank the private foundations that fund the American Dream Demonstration (ADD): founder and chair of the Corporation for Enterprise Development (CFED), conceived and produced ADD. Brian Grossman, René Bryce-Laporte, and other CFED staff have also supported the evaluation of ADD. provided consistently excellent managerial and editorial(More)
If, as hypothesized, neuroactive peptides from grain glutens are the major agents evoking schizophrenia in those with the genotype(s), it should be rare if grain is rare. To test this, we analyzed the results of our clinical examinations (e.g., kuru) and observations of anthropologists on peoples consuming little or no grain. Only two overtly insane chronic(More)
BACKGROUND Both high body fat and low muscle mass have been associated with physical disability in older adults. However, men and women differ markedly in body composition; men generally have more absolute and relative lean muscle mass and less fat mass than women. It is not known how these anthropometric differences differentially affect physical ability(More)