Brayton and others (1997) provides an accessible summary of the role and importance of expectations formation in the FRB/US model. 10 The FRB/US model is unfashionable by current academic standards in that it is not a DSGE model.
The difference that is relevant in this context is that the empirical fit of FRB/US is allowed to show through more explicitly because the modeling structure of the model is less restrictive than with a DSGE model.