The MODEL procedure now allows you to model a nonconstant error variance,
permitting the specification of ARCH- and GARCH-type regression models.
The
following features have been added to the MODEL procedure in Version 8:
- NOOLS and NO2SLS options specify bipassing using OLS or 2SLS to
get initial parameter estimates for GMM, ITGMM, or FIML. This is important
for certian models that are poorly defined in OLS or 2SLS or if good initial
parameter values are already provided. Note that for GMM, the V matrix is
created using the initial values specified and this may not be consistently
estimated.
- MSE. variables are now available for estimation and simulation.
There is a MSE. variable created for each dependent/endogenous variable in
the model. The MSE.y variable contains the value of the mean square error
for y at each iteration. These variables are used to specify the lagged values
for GARCH type models.
- Quasi-random numbers can be used to drive Monte Carlo simulation.
Quasi-random numbers are specified using the QUASI= option on the SOLVE command.
Two Quasi-random number generators supported by the MODEL procedure are the
Sobol sequence (QUASI=SOBOL) and the Faure sequence (QUASI=FAURE). The default
is QUASI=NONE which is the psuedo random number generator.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.