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From |
Maarten buis <maartenbuis@yahoo.co.uk> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: mfx- marginal effects for log linear model |

Date |
Wed, 7 Jul 2010 14:21:35 +0000 (GMT) |

--- On Wed, 7/7/10, Nyasha Tirivayi wrote: > I would like to determine the marginal effects at means for > the following model > > lnY= a + D + ln X > > where D is a dummy. How do I determine the marginal effects > at means for the log transformed variables and the dummy in > Stata? Which mfx commands in stata 10 do I use? Computing marginal effects in such a model is surprisingly difficult. Notice that you model the average ln(y) rather than the average of y, and since the logarithm is a non-linear transformation, that results in all kinds of complications. For that reason I would avoid marginal effects for this model. Instead, I would directly interpret the coefficients: the coefficient of ln(x) is an elasticity, the expected percentage change in y for a percent change in x, and 100*the coefficient of D is the percentage change in y for a unit change in D. Hope this helps, Maarten -------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://www.maartenbuis.nl -------------------------- * * 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/

**References**:**st: mfx- marginal effects for log linear model***From:*Nyasha Tirivayi <ntirivayi@gmail.com>

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