Before revision:  Estimating directly the eigenvalue and eigenfunction allows one to (1) construct empirically the time series of the  permanent and transitory components of the SDF process and (2 ) estimate the yield and the change of measure which characterize pricing over long investment horizons.
After revision:  Estimating directly the eigenvalue and eigenfunction allows one to (1) construct empirically the time series of the estimated permanent and transitory components of the SDF process and (2 ) estimate the yield and the change of measure which characterize pricing over long investment horizons.