Generalizability theory, or
G Theory, is a statistical framework for conceptualizing, investigating, and designing reliable
observations. It is used to determine the
reliability (i.e., reproducibility) of measurements under specific conditions. It is particularly useful for assessing the reliability of performance assessments. It was originally introduced in
Cronbach, L.J., Nageswari, R., & Gleser, G.C. (1963).