Hello,
I would like to ask for advice in using standardized variables (z-scores) in
cross-sectional time series analysis (xtreg).
Should z-scored be calculated over the entire sample, or should different
z-scores be calculated for each time period?
The argument for calculating z-scores by time period would focus on keeping
variables "within context."
On the other hand, it seems to me that using z-scores that are based on
different subsets of the data renders the coefficient uninterpretable. Ie. -
how can a 1 standard deviation difference be interpreted if that standard
deviation applies to only one particular year.
Any thoughts on this would be most welcomed.
Orsi Lazar
--
Orsolya K. Lazar
Dept. of Political Science
University of Arizona
Tucson, AZ 85721-0027
[email protected]
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