Population Stratification, Adjustment for

Population stratification is a major concern in genetic association studies. Failure to control it effectively can lead to excess false-positive results and failure to detect true associations. Many methods have been designed to adjust for population stratification, which mainly belong to the following categories: (1) genomic control, (2) structured association, (3) principal component or multidimensional scaling adjustment, (4) stratification score method and (5) other approaches. No method is likely to be superior in all situations. Care needs to be taken to ensure that the assumptions of the method are met and that the method is used for its intended purpose. Keywords: population stratification; genomic control; structured association; principal components; multidimensional scaling; stratification score