Regression zur Mitte

Die Rehabilitation (Impact Factor: 0.73). 08/2005; 44(04):244-251. DOI: 10.1055/s-2005-866924
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Available from: Markus Wirtz, May 06, 2014
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    • "Medical rehabilitation programmes for example, often are evaluated for their ability to restore the patient's ability to work. Unaware of RTM effects a patient's recovery typically is interpreted as a treatment effect [2]. Other examples include the evaluation of asthma disease management programmes [3] or cholesterol screening [4]. "
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    ABSTRACT: Regression to the mean (RTM) occurs in situations of repeated measurements when extreme values are followed by measurements in the same subjects that are closer to the mean of the basic population. In uncontrolled studies such changes are likely to be interpreted as a real treatment effect. Several statistical approaches have been developed to analyse such situations, including the algorithm of Mee and Chua which assumes a known population mean mu. We extend this approach to a situation where mu is unknown and suggest to vary it systematically over a range of reasonable values. Using differential calculus we provide formulas to estimate the range of mu where treatment effects are likely to occur when RTM is present. We successfully applied our method to three real world examples denoting situations when (a) no treatment effect can be confirmed regardless which mu is true, (b) when a treatment effect must be assumed independent from the true mu and (c) in the appraisal of results of uncontrolled studies. Our method can be used to separate the wheat from the chaff in situations, when one has to interpret the results of uncontrolled studies. In meta-analysis, health-technology reports or systematic reviews this approach may be helpful to clarify the evidence given from uncontrolled observational studies.
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    ABSTRACT: NAND flash memory has become an indispensable component in mobile embedded systems because of its versatile features such as nonvolatility, solid-state reliability, low cost and high density. Even though NAND flash memory is gaining popularity as data storage, it can be also exploited as code memory for XIP (execute-in-place). In this paper, we present a new memory architecture in which incorporates NAND flash memory into an existing memory hierarchy for code execution. The usefulness of the proposed approach is demonstrated with real embedded workloads on a real prototyping board.
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    ABSTRACT: According to a recent review by Hüppe and Raspe effects of multidisciplinary treatment programs for patients with chronic low back pain in Germany seem to be rather weak and not to have persisting effects. Factors which could counteract possible benefits of treatment are, among others, psychic and job-related stresses and strains persisting after treatment. A multidisciplinary, in-patient treatment program for patients with chronic low back pain, therefore, was amended by multidisciplinary diagnosis and assignment and measures to support vocational solutions. To evaluate the effects of the multidisciplinary program in comparison to a control group with the usual care, a prospective longitudinal study was conducted. 307 patients were assigned to the multidisciplinary in-patient treatment program, whereas 176 patients with comparable complaints had the standard rehabilitation program. Besides the full sample, we analyzed a subgroup of patients with chronic low back pain. We found positive moderate and strong effects in the intervention group concerning function, pain, psychic strains as well as the number of sick days and return to work rates 10 months after discharge. Effects in the intervention group exceeded the effects achieved in the control group. Beside the full sample, we analyzed a subgroup of patients with chronic low back pain, who received an intense activating group treatment. Also in this subgroup we found moderate and strong effects of treatment superior to those in the control group for function, psychic strains and sick days. We attribute these persisting and superior effects in the treatment group to an efficient treatment of occupational and psychic problems as well as to more homogeneous treatment groups attained by a multidisciplinary diagnosis and team-based assignment. They also show the significance of in-patient-treatment which is effective, when -- based on multidisciplinary diagnosis -- differential treatment groups can be formed.
    Full-text · Article · May 2006 · Zeitschrift für Orthopädie
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