A measurement model of disease severity in absence of a gold standard

In the absence of a gold standard, we propose the use of confirmatory facto r analysis for the quantification of agreement between diagnostic measureme nts and the true disease severity. The essential assumption is conditional independence of diagnostic measurements adjusted for the severity of the di sease. However, depending on the number of measurements available, the meth od works even if some of them are conditionally dependent. We illustrate th e method using an example related to glaucoma eye disease.