[Gretl-users] Univariate Time Series Structural Time Series Options

The three model selection options, Local Level, Local linear Trend and Basic structural Model all appear to give the same parameter estimates if the same combination of options regarding irregular, trend and slope are selected . Is this to be expected? If so, why the need to differentiate the three model types? Brian Brian J Revell Professor Emeritus Agricultural and Food Economics Harper Adams University Newport Shropshire TF10 8NB Tel 01952 815237 Tel: +44 1952 728153 Mbl +44 7976 538712 University: +44 1952 815235 alt: email: bjrevell(a)harper-adams.ac.uk