Did anyone see this paper:
Koken Ozaki, Hideki Toyoda, Norikazu Iwama, Saori Kubo and Juko Ando (2011). Using Non-Normal SEM to Resolve the ACDE Model in the Classical Twin Design
Thoughts? They argue that estimating skewness (3rd moment of a distribution) in addition to mean and variance, the extra degree of freedom makes ACDE models identified...
This seems over value: Can we do it in OpenMx?