RE: st: how to summarize while accounting for duplicate values

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

How do I list observations in a group that differ on a variable?
http://www.stata.com/support/faqs/data/diff.html

explains some related technique. The problem there is just the
complement of that here. 

bysort id (somevar) : gen byte same = somevar[1] == somevar[_N] 

tags panels within which -somevar- is identical by 1 and those in which
it differs by 0. 

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

dstahler@ucla.edu

Thank you to those who suggested using egen and using the first record  
for an individual.

Quoting Martin Weiss <martin.weiss1@gmx.de>:

> If this is indeed Dan`s intent, he may also like -egen, tag()-.

Jeph Herrin

> If your individuals are identified by the variable -id-,
> then create an indicator for one record per -id-:
>
>    bys id: gen first=_n==1
>
> Then all you have to do is condition on -first-
>
>   sum birthday if first
>
> to get summary stats on one record per individual.

dstahler@ucla.edu wrote:

>> I am trying to summarize a dataset in Stata 10.1 on individuals'
>> reproductive success throughout their life. The database is set up
with
>> each individual having an annual entry with multiple variables. Some
>> variables' values change annually (e.g. # offspring born), while
other
>> variables have duplicated values for each year as they do not change
>> over the course of their life (e.g. age of first reproduction,
>> lifespan). How do I get Stata to provide summary statistics for
chosen
>> variables of interest in the population that accounts for
individuals'
>> duplicated values for some variables that don't change annually?

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