In conclusion, among alternative approaches in handling correlated samples in genetic association studies, such as likelihood-based approach (Bourgain et al., 2003), sample weighting (Browning et al., 2005), and estimation equation (Trégouët et al., 1997), effective sample size is perhaps the most accessible method: easier to use, and with no need to have new computer software. Since the reason that correlated samples are often avoided in practice is not because solutions do not exist, but because the existing methods are relatively hard to use, we believe the ESS method discussed here will help medical geneticists to routinely use pedigree data in association studies.
