  We consider the problem of the identification of stationary solutions to
linear rational expectations models from the second moments of observable data.
Observational equivalence is characterized and necessary and sufficient
conditions are provided for: (i) identification under affine restrictions, (ii)
generic identification under affine restrictions of analytically parametrized
models, and (iii) local identification under non-linear restrictions. The
results strongly resemble the classical theory for VARMA models although
significant points of departure are also documented.
