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From |
Nick Cox <njcoxstata@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: computing elasticities after using lpoly |

Date |
Sat, 6 Oct 2012 10:19:37 +0100 |

It seems to me that the whole point of -lpoly- is to be flexible about modelling a relationship. It has absolutely no sense of any idea of an overall slope. If you want a number for the slope, -lpoly- is useless. If you want an independent view of how far the relationship after some smoothing really is (e.g.) linear or monotonic, then -lpoly- can be useful, mostly by providing a graph. For what you want, any appropriate regression method will be better, such as -regress- or -qreg-. Nick On Sat, Oct 6, 2012 at 10:06 AM, Arka Roy Chaudhuri <gabuisi@gmail.com> wrote: > I am using Stata 11 on a Windows 7 machine. I am using lpoly to > estimate nonparametric regressions of the form: > > log(y)=f(log(x)) + u > > where y= per capita expenditure on food > x= total per capita expenditure > > Using lpoly, I can get a graph of per capita expenditure on food > against total per capita expenditure. However I am also interested in > obtaining expenditure elasticities of percapita expenditure on food at > different levels of total per capita expenditure i.e in my context > d(log(y)/d(log(x)) where x and y are as earlier defined.The problem is > that lpoly does not give estimates of any slope coefficients so I am > at a loss on how to compute these elasticities. I would really > appreciate if anybody could give me advice in this regard. > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: computing elasticities after using lpoly***From:*Arka Roy Chaudhuri <gabuisi@gmail.com>

**References**:**st: computing elasticities after using lpoly***From:*Arka Roy Chaudhuri <gabuisi@gmail.com>

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