Joanne Emerson

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Meta-analytic investigations sometimes use assessments of research quality according to a formal protocol as a tool for improving research synthesis. We asked whether a particular quality scoring system could have a direct use in adjusting the summary estimates of a treatment difference. In an empirical study of the relation of quality scores to treatment(More)
Readers need information about the design and analysis of a clinical trial to evaluate and interpret its findings. We reviewed 84 therapeutic trials appearing in six general surgical journals from July 1981 through June 1982 and assessed the reporting of 11 important aspects of design and analysis. Overall, 59% of the 11 items were clearly reported, 5% were(More)
A sorting of the statistical methods used by authors of the 760 research and review articles in Volumes 298 to 301 of The New England Journal of Medicine indicates that a reader who is conversant with descriptive statistics (percentages, means, and standard deviations) has statistical access to 58 per cent of the articles. Understanding t-tests increases(More)
BACKGROUND Use of protocols to reduce weaning time for patients receiving mechanical ventilation helps reduce cost and length of stay. However, implementation of this type of protocol is not easy and requires a consistent collaborative effort. OBJECTIVE To provide a systematic approach to the weaning process by developing, implementing, and evaluating a(More)
Meta-analyses often use a random-effects model to incorporate unexplained heterogeneity of study results. Trimmed versions of meta-analytic estimators for the risk difference, adapted from procedures designed for a random-effects analysis, can resist the impact of a few anomalous studies. A simulation study compared untrimmed and trimmed versions of four(More)
Medical students and doctors need training in biostatistics. The use of analytic statistics in a leading general medical journal is reported. Of 760 consecutive research and review articles, 42% use statistical methods beyond elementary descriptive statistics. Critical reading of the medical literature requires an understanding of many statistical methods.(More)
Biological and medical investigations often use ordered categorical data. When two groups are to be compared and the data for the groups fall in three or more ordered categories, the Wilcoxon-Mann-Whitney (WMW) test uses information in the ordering to give a test that is usually powerful against shift alternatives. However, such applications of WMW often(More)
Clinical investigations often involve data in the form of ordered categories--e.g., "worse," "unchanged," "improved," "much improved." Comparison of two groups when the data are of this kind should not be done by the chi-square test, which wastes information and is insensitive in this context. The Wilcoxon-Mann-Whitney test provides a proper analysis.(More)
Exchange transfusion of blood (75-80% replacement of blood of recipient animals) was used to study the effect of blood-borne influences on nuclear labeling with thymidine-3H and on occur rence of mitosis in hepatocytes of rat liver. Intact or shamhepatectomized rats and partially hepatectomized rats were: (a) not transfused, (6) transfused with blood from(More)
Medical research commonly relies on the combination of 2 x 2 tables of counted data for making inferences about treatment effects or about the causes of disease. This article reviews point estimation and interval estimation for a common odds ratio. Traditional methods for providing these estimates face special challenges, and sometimes break down, when the(More)