Fig. 1.

Multivariate models: (a) longitudinal Cholesky decomposition, (b) Common pathway model. A, Additive genetic effects; E, non-shared environmental effects, Var, variable. Subscript ‘l’ denotes stable influences on the latent factor, subscript ‘s’ denotes variable- and time-specific influences. In panel (a), variance paths, which must be squared to estimate the proportion of variance accounted for, are represented by lowercase letters and followed by two numerals, e.g. a1₁, c2₂, e3₃. In panel (b), only three variables are presented for clarity; however the model was run with all five variables included, each measured at three time points.