Genetic variation analysis Collapsing methods Genome-wide association studies (GWAS) analyse a genome-wide set of genetic variants in different individuals to see if any variant is associated with a trait. Traditional association techniques can lack the power to detect the significance of rare variants individually, or measure their compound effect (rare variant burden). "Collapsing methods" were developed to overcome these problems. A method whereby data on several variants are "collapsed" into a single covariate based on regions such as genes. 1.17