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From |
"Nick Cox" <n.j.cox@durham.ac.uk> |

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

Subject |
st: RE: Stata coding |

Date |
Mon, 13 Apr 2009 13:40:19 +0100 |

-egen- does not drop, meaning -drop-, observations that do not satisfy an -if- condition; it merely ignores them. In this example, I will for illustration take it that -if native == 1- specifies that people are natives. You should of course substitute your own correct syntax. There are various ways to attack your first problem. Here is one. bysort country : egen float nativeattitudes = mean(attitudes) if native == 1 bysort country (nativeattitudes) : replace nativeattitudes = nativeattitides[1] Here is another. bysort country: egen nativeattitudes = mean(cond(native == 1, attitudes, .)) The answer to your second problem is yes, if I understand it correctly. Just put two or more variables in your variable list fed to -by:-. Nick n.j.cox@durham.ac.uk Rahsaan Maxwell, Ph.D. Does anyone know if there is a fast way to code new variables in Stata so that they equal the mean value of a subpopulation's score on particular other variables? For example, I am analyzing two main subpopulations: migrants and natives. Both of which are nested in countries and regions. I want to calculate a new variable which captures the mean attitudes of natives in each country/region and then use that as an independent variable in a model predicting migrant outcomes. I have used the code below to calculate mean attitudes of the entire population for country/region but I can't figure out how to make that calculation apply to only one subgroup yet still have the variable be valid for the whole population. (If I add an 'if' clause at the end of the code it will drop all cases that don't apply). by country, sort : egen float countryattitudes = mean(attitudes) by region, sort : egen float regionattitudes = mean(attitudes) I have been calculating subgroup means 'by hand' and then manually writing code for the countries. Which is slow. But I have almost 300 regions and multiple variables so I'm wondering if there is a faster way to do this? And more generally, is it possible to create a new variable with multiple values per country/region for means across different groups. I.E. I want country1 to have one value for the mean attitude of natives and another value for the mean attitude of migrants. I want to do this in order to graph migrant/native means across the countries and regions. * * 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: Stata coding***From:*Rahsaan Maxwell <rahsaan@polsci.umass.edu>

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