SIMU_REGRESSION combines two or more existing regression models
into a simultaneous regression system. Each equation is estimated separately,
but the command reports the system as a unified model with cross-equation
residual diagnostics.
SIMU_REGRESSION(regression1, regression2, ...)
r1 = REGRESSION(LIST(LOGDIFF(CPIAUCSL), LOGDIFF(PPIACO), LOGDIFF(M2SL)))
r2 = REGRESSION(LIST(LOGDIFF(PCE), LOGDIFF(CPIAUCSL), LOGDIFF(PAYEMS)))
s = SIMU_REGRESSION(r1, r2)
EX(s, slideshow)
A simultaneous regression system is useful when several economic or financial relationships should be viewed together rather than as isolated regressions. The command displays each equation, model coefficients, fitted values, residuals, autocorrelation diagnostics, and system-level residual covariance and correlation matrices.
The residual correlation matrix is the key diagnostic. If residuals are strongly correlated across equations, a system estimator such as SUR or 3SLS may improve efficiency or better represent the structure of the model.
EX(s, slideshow)
EX(s, residual_correlation)
EX(s, residual_covariance)
SIMU_REGRESSION is currently a system wrapper around existing
regression operators. It does not yet re-estimate the equations jointly.
Future versions may support SUR, 2SLS, and 3SLS estimation using the same
system structure.