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From | Richard Williams <richardwilliams.ndu@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: Marginal Effects using subsetted data |
Date | Sun, 31 Oct 2010 19:37:18 -0500 |
At 02:54 PM 10/31/2010, MOSTARDO, NICK wrote:
Hello, I am running an ordered probit model using data that I wish to subset by gender and race (both dichotomous measures). I am running the following commands: 'by gender race, sort: ologit depvar indvars' At that point, I get the correct output of 4 tables for the proper combinations of the sorted variables (0,0)(0,1)(1,0)(1,1); however, when I try to run marginal effects as: 'mfx, predict(p outcome(1))' (my depvar is 3 ordered categories) I get the error: 'no observations r(2000);'
As a sidelight, you might want to use mfx2 or margeff instead of mfx when running commands like oprobit. Both will give you the marginal effects for all the outcomes at once, instead of having to give a command for each outcome. Both also give you the option of storing the results, which can be handy for creating tables. Both are available from SSC. Slightly tweaking Kit's example,
clear all set more off sysuse auto drop if rep78==1 su price,mean g hip = price>r(mean) forv p=0/1 { forv f=0/1 { di in r _n "High price==`p', Foreign==`f'" oprobit rep78 turn mpg if hip==`p' & foreign==`f', nolog mfx, predict(p outcome(#1)) mfx2, nolog } }If I ever get ambitious, I may try to update mfx2 so it works with factor variables and the margins command. Having to give separate commands for each outcome is kind of a pain and it makes the output harder to read.
------------------------------------------- Richard Williams, Notre Dame Dept of Sociology OFFICE: (574)631-6668, (574)631-6463 HOME: (574)289-5227 EMAIL: Richard.A.Williams.5@ND.Edu WWW: http://www.nd.edu/~rwilliam * * 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/