jpfeifer wrote:Dear Huan,
why should that be a problem? A case like this occurs whenever you want to estimate the mean growth rate in an observation equation using first differences.
Many thanks Johannes.
In my model , I have financial friction but do Not have a good corresponding financial data. If I use linear detrended interest rate spread data as an "instrument" , and set a new parameter measuring the volatility difference between data and model variable in measurement equation , maybe also put an measurement error there, shown as below
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interest rate spread_obs= (constant x )* model financial friction variable + measurement error
,
(model is log-linearized)
Then estimate the constant x (only appears in measurement equation) and standard deviation of measurement error, would that be a problem?
Kind regards,
Huan