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From |
Rodolphe Desbordes <rodolphe.desbordes@strath.ac.uk> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: RE: Interpretation of quadratic terms |

Date |
Fri, 12 Mar 2010 11:55:42 +0000 |

Dear Michael, In that case, -margins- behaviour is slightly puzzling. Could the absence of output be explained by the fact that the year 1970 did not exist in your sample? . sysuse nlsw88, clear (NLSW, 1988 extract) . . generate year = age + 1968 . end of do-file . tab year year | Freq. Percent Cum. ------------+----------------------------------- 2002 | 53 2.36 2.36 2003 | 260 11.58 13.94 2004 | 257 11.44 25.38 2005 | 225 10.02 35.40 2006 | 219 9.75 45.15 2007 | 234 10.42 55.57 2008 | 208 9.26 64.83 2009 | 222 9.88 74.71 2010 | 160 7.12 81.83 2011 | 165 7.35 89.18 2012 | 163 7.26 96.44 2013 | 78 3.47 99.91 2014 | 2 0.09 100.00 ------------+----------------------------------- Total | 2,246 100.00 Best regards, Rodolphe ________________________________________ From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] On Behalf Of Michael Norman Mitchell [Michael.Norman.Mitchell@gmail.com] Sent: 12 March 2010 07:33 To: statalist@hsphsun2.harvard.edu Subject: Re: st: RE: Interpretation of quadratic terms Dear Rodolphe Thanks for your message. I think it is possible that you read a little bit more into my message than I intended... I was not purporting to compute marginal effects, and hence did not use the "dydx()" option. I was just showing how to compute the predicted value of "y" for a given value of "x". That is another way that the margins command can be used. Best regards, Michael N. Mitchell See the Stata tidbit of the week at... http://www.MichaelNormanMitchell.com On 2010-03-11 8.32 AM, Rodolphe Desbordes wrote: > Dear Eric, > > I apologise for my lack of clarity regarding the -margins- command. Even though I have hardly used it, exchanges on the Statalist have made it clear that -margins- can do many things, including the calculation of marginal effects. However Michael did not seem to have used the correct syntax; I believe that the option "dydx" must be used to obtain marginal effects. > > Rodolphe > > ________________________________________ > From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] On Behalf Of DE SOUZA Eric [eric.de_souza@coleurope.eu] > Sent: 11 March 2010 15:01 > To: 'statalist@hsphsun2.harvard.edu' > Subject: RE: st: RE: Interpretation of quadratic terms > > Dear Rodolphe, > > I don't have Stata 11 either. But according to the preface to the new edition of Cameron and Trivedi, Microeconometrics using Stata: > "Second, we describe the new margins command for prediction and for computation of > marginal effects in regression models. The margins command with options including the > dydx() option replaces the Stata mfx command and the user-written margeff command. > Additionally, the margins command when used in conjunction with factor variables can > simplify computation of marginal effects in models with interactions. " > > So the margins command is Stata 11 does allow one to calculate marginal effects > > Eric de Souza > College of Europe > BE-8000 Brugge (Bruges) > Belgium > > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Rodolphe Desbordes > Sent: 11 March 2010 14:59 > To: statalist@hsphsun2.harvard.edu > Subject: RE: st: RE: Interpretation of quadratic terms > > I do not have Stata 11 installed on this computer and I am not vary familiar with the -margins- command. However, using -margins-, you did not calculate the marginal effect but the predicted value of wage, at a given value of age. > > > * > * 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/ > * * 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/

**Follow-Ups**:**Re: st: RE: Interpretation of quadratic terms***From:*Michael Norman Mitchell <Michael.Norman.Mitchell@gmail.com>

**References**:**Re: st: RE: Interpretation of quadratic terms***From:*Rosie Chen <jiarongchen2002@yahoo.com>

**RE: st: RE: Interpretation of quadratic terms***From:*Rodolphe Desbordes <rodolphe.desbordes@strath.ac.uk>

**RE: st: RE: Interpretation of quadratic terms***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

**Re: st: RE: Interpretation of quadratic terms***From:*Michael Mitchell <Michael.Norman.Mitchell@gmail.com>

**RE: st: RE: Interpretation of quadratic terms***From:*Rodolphe Desbordes <rodolphe.desbordes@strath.ac.uk>

**RE: st: RE: Interpretation of quadratic terms***From:*DE SOUZA Eric <eric.de_souza@coleurope.eu>

**RE: st: RE: Interpretation of quadratic terms***From:*Rodolphe Desbordes <rodolphe.desbordes@strath.ac.uk>

**Re: st: RE: Interpretation of quadratic terms***From:*Michael Norman Mitchell <Michael.Norman.Mitchell@gmail.com>

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