Nonparametric sequential monitoring of longitudinal trials.
Summary of "Nonparametric sequential monitoring of longitudinal trials."
This paper considers the sequential monitoring of multi-armed longitudinal clinical trials. We describe an approach that is relatively simple and accessible. Sequential ranks are used to form partial sum statistics, yielding processes that have independent increments, and hence can be approximated by Brownian motions. Three monitoring procedures are proposed. The first two are asymptotic, continuous analogues of the well-known Pocock and O'Brien-Fleming group sequential procedures, whereas the third procedure is exact. Performance of the procedures is assessed using Monte Carlo simulations. Data from an orthodontic clinical trial is used to illustrate the proposed methods, for the comparison of three treatment groups.
Department of Mathematical and Statistical Sciences, Faculty of Science, University of Alberta, Edmonton, AB T6G2G1, Canada.
This article was published in the following journal.
Name: Statistics in medicine
Medical and Biotech [MESH] Definitions
Clinical Trials Data Monitoring Committees
Committees established to review interim data and efficacy outcomes in clinical trials. The findings of these committees are used in deciding whether a trial should be continued as designed, changed, or terminated. Government regulations regarding federally-funded research involving human subjects (the "Common Rule") require (45 CFR 46.111) that research ethics committees reviewing large-scale clinical trials monitor the data collected using a mechanism such as a data monitoring committee. FDA regulations (21 CFR 50.24) require that such committees be established to monitor studies conducted in emergency settings.
A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)
Two extensive fibrous bands running the length of the vertebral column. The anterior longitudinal ligament (ligamentum longitudinale anterius; lacertus medius) interconnects the anterior surfaces of the vertebral bodies; the posterior longitudinal ligament (ligamentum longitudinale posterius) interconnects the posterior surfaces. The commonest clinical consideration is OSSIFICATION OF POSTERIOR LONGITUDINAL LIGAMENT. (From Stedman, 25th ed)
Physiologic or biochemical monitoring of the fetus. It is usually done during LABOR, OBSTETRIC and may be performed in conjunction with the monitoring of uterine activity. It may also be performed prenatally as when the mother is undergoing surgery.
Ossification Of Posterior Longitudinal Ligament
A calcification of the posterior longitudinal ligament of the spinal column, usually at the level of the cervical spine. It is often associated with anterior ankylosing hyperostosis.
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