Otis Dudley Duncan introduced SEM to the social sciences in 1975 and it flourished throughout the 1970s and 80s. Different yet mathematically related modeling approaches developed in psychology, sociology, and economics. The convergence of two of these developmental streams (factor analysis from psychology, and path analysis from sociology via Duncan) produced the current core of SEM although there is great overlap with econometric practices employing simultaneous equations and exogenous (causal variables).
