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From |
Dorothy Bridges <dbstata@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: AW: AW: Creating a variable taking the value of elasticity |

Date |
Tue, 8 Sep 2009 12:31:41 -0400 |

Yes, clearly I need to give this more thought -- thanks again all for the coding assistance. On Tue, Sep 8, 2009 at 12:02 PM, Austin Nichols<austinnichols@gmail.com> wrote: > Dorothy Bridges<dbstata@gmail.com>: > The main problem I see there is one of inferring causality--does an > exogenous increase in GDP cause an increase in "health" or does an > increase in "health" cause increased production or does some other > factor increase both? You might want -xtivreg- but then you need > appropriate excluded instruments... > > On Tue, Sep 8, 2009 at 11:10 AM, Dorothy Bridges<dbstata@gmail.com> wrote: >> Thanks so much, everyone, that answers my question. (And thanks Roger >> for pointing me to the helpful package). I have one last question: I >> am trying to understand the "elasticity" of a health indicator with >> respect to GDP (that is, how does a marginal increase in GDP affect >> the health indicator?). If I regress ln(healthindicator) on ln(gdp), >> is the coefficient on ln(gdp) an appropriate way of measuring this >> elasticity? I realize this is more of an econometrics question than a >> Stata question, but everyone has been so helpful I thought I'd might >> as well ask. >> >> Thanks again, >> Dorothy >> >> On Tue, Sep 8, 2009 at 10:52 AM, Austin Nichols<austinnichols@gmail.com> wrote: >>> Dorothy Bridges<dbstata@gmail.com>: >>> The linear model and the log-log model make very different assumptions >>> about the data-generating process, so you should not expect to get the >>> same estimates from them. -mfx- after a linear model in particular >>> will give approximate estimates that are very questionable--note that >>> if the true model is >>> y=Xb+e >>> then the elasticity of y with respect to x (a variable, or column of >>> X) will vary as x varies. >>> >>> On Tue, Sep 8, 2009 at 10:32 AM, Dorothy Bridges<dbstata@gmail.com> wrote: >>> I still >>>> don't see, then, how mfx, eyex gives me a value different than the >>>> coefficient on lnx in regress lny lnx. Thanks again for all your >>>> thoughts. > > * > * 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/

**References**:**Re: st: AW: AW: Creating a variable taking the value of elasticity***From:*Dorothy Bridges <dbstata@gmail.com>

**Re: st: AW: AW: Creating a variable taking the value of elasticity***From:*Maarten buis <maartenbuis@yahoo.co.uk>

**Re: st: AW: AW: Creating a variable taking the value of elasticity***From:*Dorothy Bridges <dbstata@gmail.com>

**Re: st: AW: AW: Creating a variable taking the value of elasticity***From:*Austin Nichols <austinnichols@gmail.com>

**Re: st: AW: AW: Creating a variable taking the value of elasticity***From:*Dorothy Bridges <dbstata@gmail.com>

**Re: st: AW: AW: Creating a variable taking the value of elasticity***From:*Austin Nichols <austinnichols@gmail.com>

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