The finding that an independent model best explained the shared variance between dimensions highlights both shared and unique etiological influences. If a common pathway model had fit best, shared etiology of the OC dimensions would have been attributable to a latent trait (e.g., OC traits). If that were true, it would be necessary to calculate a latent trait for genetic studies rather than studying individual dimensions. OC dimensions can be highly correlated and still fit an independent model. Both independent and common models demonstrate that the co-variance between dimensions can be accounted for in part by shared genetic factors. However, in the independent model, those shared genetic factors influence each dimension directly, whereas in the common model these shared genetic factors are so closely related that they influence each dimension through a common factor. Results from previous studies in adults on the fit of the common and independent pathway for OC traits are mixed15,16. An important difference seems to be the number of OC dimensions captured by the scale they used—an independent model fits best when there were more dimensions15,
