st: RE: correct egen command to calculate means - please help

[Nick Cox <n.j.cox@durham.ac.uk>]

I don't understand your pseudocode. It looks like 

Y = mean(X) where A = B 

to me. 

Nor is it "obvious" that 

egen MeanRevenueParent=mean(Revenue), by(ParentIndustry)

is wrong. From your word description it sounds exactly right to me! 

Please give a worked example of what you want for a minimal dataset. 

Note that explanations that assume proficiency in Excel _and_ Stata catch a much smaller set of people than explanations that assume proficiency in Stata. 

(Can we assume that income == revenue?) 

Nick 
n.j.cox@durham.ac.uk 

Ophelie Desmarais

I have tried to find an answer for this on the web but to no avail.

Simplified, I have following dataset where the unit of observation is
the industry (IndustryID) with the respective revenue.

IndustryID, ParentIndustryID, Revenue


The ParentIndustryID links to IndustryID and reflects the hierachical
structure of the industries. For each industry, I want to add a
variable reflecting the mean income of the ParentIndustryID. How do I
do this in Stata? In Excel, this would be simply using AVERAGEIFS.
egen MeanRevenueParent=mean(Revenue), by(ParentIndustry) obviously
does not give the right mean. In terms of pseudo code, this should be
something like:

MeanRevenueParent = Mean(Revenue) WHERE ParentIndustry=IndustryID

Could anyone help me out? I don't want to switch around with Excel all the time.


*
*   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/