This sample-wide estimation and visualization of genetic ancestry can be used to empirically assign genetically similar samples into more homogenous groups. This assignment is necessary for the stratified meta-analysis approach to GWAS of diverse cohorts, and is intended to reduce the risk of false positive genetic signals due to inflated test statistics from population stratification. Assigning samples to more homogeneous groups for analysis reduces stratification by limiting the degree of population structure remaining in the sample. Samples with a specific admixture can be assigned into their own major ancestral group, instead of being excluded from the analysis or forced into other ancestry groups, provided there are adequate numbers of individuals in the sample with comparable admixed backgrounds. However, it is often the case that genomic outliers (which tend to be from under-represented or admixed backgrounds) might need to be excluded if there is an insufficient number of other individuals who fall into a similar cluster. These assignment methods will not provide - and are not intended to provide - detailed ancestral background information for each individual. Rather, they provide a
