Ward, David G.2011-04-062011-04-061986Ward, David G. (1986). Factor indeterminacy in generalizability theory. Applied Psychological Measurement, 10, 159-165. doi:10.1177/014662168601000206doi:10.1177/014662168601000206https://hdl.handle.net/11299/102295Generalizability theory and common factor analysis are based upon the random effects model of the analysis of variance, and both are subject to the factor indeterminacy problem: The unobserved random variables (common factor scores or universe scores) are indeterminate. In the one-facet (repeated measures) design, the extent to which true or universe scores and common factor scores are not uniquely defined is shown to be a function of the dependability (reliability) of the data. The minimum possible correlation between equivalent common factor scores is a lower bound estimate of reliability.enArticle