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From | e156746@metu.edu.tr |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: RE: Frontier code- r(1400) error |
Date | Sat, 2 Apr 2011 23:59:30 +0300 (EEST) |
Dear Nick and Gordon Thank you for your advices. But Gordon says that "you have only 29 observations". I might have expressed myself in an incorrect way. I have 4 output variables, 3 input price variables for the 29 firms. Actually I have 208 observations. It seems enough to estimate the frontier, isn't it ? Thank you Hande > Nick's answer is correct. You have 27 parameters plus the additional > parameters for the efficiency error distribution and only 29 > observations. This will never produce a satisfactory result. > > Translog frontier models can be difficult to estimate under the best > of circumstances without trying to over-determine the frontier. You > should start by estimating the basic log-linear Cobb-Douglas form > (dropping all of the interaction terms) and then introduce > interactions individually and very carefully. Even then it is > unlikely that you will get any convincing results with such a small > sample. > > Gordon Hughes > g.a.hughes@ed.ac.uk > > * > * 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/ > * * 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/