“…Equations (2) and (3) are jointly estimated using the varying‐coefficient (VC) model proposed by Schlicht (
2003). In this approach, the variances
are calculated by a method‐of‐moments estimator that coincides with the maximum‐likelihood estimator via the Kalman filter if the time series are sufficiently long and if the variance ratios are properly estimated (see Schlicht & Ludsteck,
2006; Schlicht,
2003 for more details). This VC method can be viewed as a straightforward generalization of the method of least squares.…”