G_String is a user-friendly Windows® application that uses R. L. Brennan's urGENOVA application to apply Generalizability theory to the analysis of data sets. The latest version can also provide D Study coefficients. G_String was designed and coded by Dr. Ralph Bloch.

urGENOVA is an ANSI C computer program for the estimation of variance components for unbalanced, random-effects G Study designs. The program does not have D Study capabilities. urGENOVA was designed and coded by R. L. Brennan.