Additionally, the results from each tool in Pedwiz will be useful for later analysis of phenotype and/or genotype data. As stated before, an essential part of score tests is the choice of the denominator variance, and some of these tests for genetic linkage require the variance-covariance of the coefficients of IBD. No software tools are currently available to provide this information independent of the choice of test statistics. The variance-covariance of the genetic similarity tool of PedWiz provides this need, so that it can be used for different choices of test statistics. The information from the genetic similarity tool of PedWiz can be used for weighting pedigrees of different sizes. Another potential use of this tool is for selecting families with the most information in terms of genetic relatedness that would best suit a phenotype/genotype analysis of choice. Selecting families with multiple affected subjects, or families with extreme values, is known to provide improved ability to measure, and detect, the effects of rare variants (Ionita-Laza and Ottman, 2011; Wijsman, 2012). The strategy of selecting “large linked families” for initial screening has long been a successful strategy (Bowden et al., 2010). To be successful with this approach, selecting families with a real linkage signal in specific regions is essential. This new tool will be useful for selecting such families when used together with phenotype/genotype information.