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Biomedical subjects

I Olkin

Publications and source records attributed to I Olkin.

29 records · Page 2Linked to original sources
PubMed1995

Statistical and theoretical considerations in meta-analysis.

An historical perspective of statistical methods for combining the results of independent studies is provided. The information explosion subsequent to 1950 has been a critical factor in the development of the field. An example of a meta-analysis is used to illustrate all alternative analyses that should be considered for conducting a meta-analytic study.

Analysis of Variance↗
PubMed1993

Multivariate assessment of computer-analyzed corneal topographers.

Methodological aspects of multivariate statistical models to describe and to assess data from computer-analyzed corneal topographers (CACT) are considered. The data generated by repeated curvature mappings of calibrated steel balls are discussed in detail with the objective of formulating the basic questions and suggesting directions to assess data from clinical applications of CACT. The interpretation of seemingly straightforward concepts such as accuracy and precision is revisited with the objective of understanding its meaning in future clinical and experimental applications of CACT. Some of the statistical problems related to the analysis of corneal astigmatism based on CACT data are also discussed.

Astigmatism↗
PubMed1977

A study of X chromosome linkage with field dependence and spatial visualization.

The purposes of this report are to describe a design for the study of X linkage, to illustrate its application using cognitive test scores, and to offer a linkage hypothesis suggested by these data. Sixty-seven three-son families were examined for two X chromosome marker variables--red-green color vision and Xg(a) blood groups--and given a battery of cognitive tests of field dependence and spatial visualization abilities. Evidence was found to suggest that brothers who are identical in Xg(a) phenotype are more similar to each other in extent of field dependence than brothers who are different in Xg(a) phenotype. This result is tentative because of the small number of informative cases and the many linkage associations examined. If cross-validated, such a finding would be consistent with the proposition that an X chromosome gene contributes to the field dependence cognitive style.

Blood Group Antigens↗
PubMedDate not supplied

Diagnostic statistical procedures in medical meta-analyses.

The number of published meta-analyses in medicine has had phenomenal growth, to a point where over 300 meta-analyses in medicine are published yearly. Because meta-analyses tend to lead to policy decisions, it is extremely important that the analyses be robust and that alternative analyses yield consistent results. We herein provide a discussion of diagnostic statistical procedures.

Confidence Intervals↗
PubMedDate not supplied

[Improving the quality of reports of meta-analyses of randomized controlled trials: the QUOROM Statement].

BACKGROUND: The Quality of Reporting of Meta-analyses (QUOROM) Conference was convened to address standards for improving the quality of reporting of meta-analyses of clinical randomised controlled trials (RCTs). METHODS: The QUOROM group consists of 30 clinical epidemiologists, clinicians, statisticians, editors, and researchers. In conference, the group was asked to identify items they thought should be included in a checklist of standards. Whenever possible, checklist items were guided by research evidence suggesting that failure to adhere to the item proposed could lead to biased results. A modified Delphi technique was used in assessing candidate items. RESULTS: The conference resulted in the QUOROM statement, a checklist, and a flow diagram. The checklist describes our preferred way to present the abstract, introduction, methods, results, and discussion sections of a report of a meta-analysis. it is organized into 21 headings and subheadings regarding searches, selection, validity assessment, data abstraction, study characteristics, and quantitative data synthesis, and in the results with 'trial flow', study characteristics, and quantitative data synthesis; research documentation was identified for eight of the 18 items. The flow diagram provides information about both the numbers of RCTs identified, included, and excluded and the reasons for exclusion of trials. INTERPRETATION: We hope this report will generate further thought about ways to improve the quality of reports of meta-analyses of RCTs and that interested readers, reviewers, researchers, and editors will use the QUOROM statement and generate ideas for its improvement.

Meta-Analysis as Topic↗
PubMedDate not supplied

[Improving the quality of reports on randomized controlled trials. Recommendations of the CONSORT Study Group].

This summary corresponds to the translation into Spanish of the Special Communication published in the Journal of the American Medical Association in August 1996, along with the editorial published in the same issue "How to report Randomized Controlled Trials. The Consort Statement". It describes the Consolidated Standards for Preparation of Controlled Clinical Trials, prepared by a work group made up of members of the SORT Group and of the Asilomar Work Group, along with the director of a magazine and the author of the report on a clinical trial. The work was carried out by means of a Delphi process and the result was a check list and a process diagram. The check list is made up of 21 items that mainly refer to methods, results and discussions on the report of a controlled clinical trial, identifying the necessary information in order to be able to evaluate the internal and external value of the report, judging the improvement to be positive for the patient, the editors and the reviewers of the magazines.

Delphi Technique↗