This attitude
was very much reminiscent of the approach adopted earlier by Tinbergen in his business
cycle research: the function of economic theory was to provide the specification of the
econometric model, and that of econometrics to furnish statistically optimal methods
of estimation and inference. More specifically, at the Cowles Commission the primary
task of econometrics was seen to be the development of statistically efficient methods for
the estimation of structural parameters of an a priori specified system of simultaneous
stochastic equations.