Figure A2.

Data-generating model (with means): The data-generating model with bidirectional first-order causal effects between X and Y ($b_{YX}$ and $b_{XY}$) simulated over 150 time points. The instrumental variable for X, IVx, has an unchanging direct effect on X ($b_X$) at every time point. Likewise, the instrumental variable for Y, IVy, directly affects Y ($b_Y$) at all time points. Squares/rectangles represent the observed variables, and circles represent latent variables (i.e., the variances in this model). Triangles represent constants used to model the variables’ mean levels.