Showing papers by "Ingram Olkin published in 1996"

Improving the quality of reporting of randomized controlled trials. The CONSORT statement.

Abstract: THE RANDOMIZED controlled trial (RCT), more than any other methodology, can have a powerful and immediate impact on patient care. Ideally, the report of such an evaluation needs to convey to the reader relevant information concerning the design, conduct, analysis, and generalizability of the trial. This information should provide the reader with the ability to make informed judgments regarding the internal and external validity of the trial. Accurate and complete reporting also benefits editors and reviewers in their deliberations regarding submitted manuscripts. For RCTs to ultimately benefit patients, the published report should be of the highest possible standard. For editorial comment see p 649. Evidence produced repeatedly over the last 30 years indicates a wide chasm between what a trial should report and what is actually published in the literature. In a review of 71 RCTs with negative results published between 1960 and 1975, the authors reported that the vast

Models for estimating the number of unpublished studies

Abstract: The possible existence of unreported studies can cast doubt on the conclusions of a meta-analytic summary of the literature, particularly if there is reason to believe that there is a publication bias against non-significant results. The present article proposes two general models that describe how the preponderance of published studies could report significant p-values even when testing a null hypothesis that is, in fact, true. Each such model allows one to estimate the number, N, of unpublished studies using the p-values reported in the published studies; the meta-analyst can then evaluate the plausibility of this estimated value of N, or related confidence bounds. Use of models of the kind suggested here allows meta-analysts to assess the problem of unpublished studies from various perspectives and thus can lead to greater understanding of, and confidence in, meta-analytic conclusions.

Meta-analysis: current issues in research synthesis.

Abstract: Recent concern about the effectiveness of alternative treatments in medicine and health, in education, in psychology, and in the social sciences has led to a consideration of how to combine or synthesize the results of independent studies. Historically, integration of independent results focused on how to combine p-values. More recently the emphasis has been on estimating effect sizes, which in turn has motivated a variety of alternative models depending on the experimental conditions. We here review the development of the field with an emphasis of diagnostics and future research.

When Does A*A = B*B and Why Does One Want to Know?

Abstract: (1996). When Does A*A = B*B and Why Does One Want to Know? The American Mathematical Monthly: Vol. 103, No. 6, pp. 470-482.

Asymptotic aspects of ordinary ridge regression

Abstract: SYNOPTIC ABSTRACTOrdinary ridge regression is considered as an alternative to least squares regression for the analysis of multicollinear data. When the ridge factor is estimated from the data, we obtain the asymptotic distribution of several ridge factors, and propose a new ridge factor based on asymptotic considerations. The mean squared errors of operational ordinary ridge regression estimators are evaluated asymptotically, and we propose several statistics useful for the selection of ridge factors.