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| From | Fabio Zona <fabio.zona@unibocconi.it> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | st: collinearity adjustment |
| Date | Mon, 15 Mar 2010 09:27:37 +0100 (CET) |
Dear Statlists centering variables around their means is a standard procedure to solve the problem of multicollinearity which arises when dealing with interaction terms and linear/quadratic terms. I tried to center my variables, but, after centering, -collin- commands tell VIF values are still very high; maybe it depends on the fact that in my database there are thousands of zero-observations, and the mean is very close to zero: as a consequence, subtracting the mean from the variable does not change it enough to solve the problem of multicollinearity. Is my interpretation correct? Any idea on how I might solve this problem? Thanks a lot * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/