Curses-winner's and otherwise-in genetic epidemiology

Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA.
Epidemiology (Cambridge, Mass.) (Impact Factor: 6.18). 10/2008; 19(5):649-51; discussion 657-8. DOI: 10.1097/EDE.0b013e318181b865
Source: PubMed

ABSTRACT The estimated effect of a marker allele from the initial study reporting the marker-allele association is often exaggerated relative to the estimated effect in follow-up studies (the "winner's curse" phenomenon). This is a particular concern for genome-wide association studies, where markers typically must pass very stringent significance thresholds to be selected for replication. A related problem is the overestimation of the predictive accuracy that occurs when the same data set is used to select a multilocus risk model from a wide range of possible models and then estimate the accuracy of the final model ("over-fitting"). Even in the absence of these quantitative biases, researchers can over-state the qualitative importance of their findings--for example, by focusing on relative risks in a context where sensitivity and specificity may be more appropriate measures. Epidemiologists need to be aware of these potential problems: as authors, to avoid or minimize them, and as readers, to detect them.

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