Re: st: Identify observations within a variable

[Jeph Herrin <stata@spandrel.net>]

Sounds like what you want is:

 by artist isrc_country : egen country_sales=total(sales)
 by artist (country_sales) : gen origin=isrc_country[_N]

this will assign the country that has the most sales, not the most observations, as the -origin-.

hth,
Jeph


On 4/22/2013 10:08 AM, Estrella Gomez wrote:
> Hi, Nick
>
> One additional question: I guess that
>
> by artist: egen origin = mode (isrc_country)
>
> where isrc_country is the country of origin, shows for each artist the
> origin country that is more frequent. Is it possible to weight this
> measure according to the number of total sales?
>
> This is an example of what I mean: there are many observations in
> which the number of sales is only one. Then if there are, say, 200
> observations with one sale for Shakira originally recorded as from
> Colombia, but one observation with 300 sales for Shakira originally
> recorded as from USA, the egen command would interpret that Shakira is
> from Colombia, when it is more reasonable to attribute an US origin in
> this case.
>
> Thanks a lot,
> Estrella
>
>
> 2013/4/22 Nick Cox <njcoxstata@gmail.com>:
> > As I understand it you want to replace differing values by the most
> > commonly occurring value. This is just the mode and the -mode()-
> > function of the -egen- command should suffice.
> >
> > It has supported string arguments too since birth.
> >
> > That aside your question is an FAQ
> >
> > FAQ     . . . . . .  Listing observations in a group that differ on a variable
> >          . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N. J. Cox
> >          11/01   How do I list observations in a group that differ
> >                  on a variable?
> > http://www.stata.com/support/faqs/data-management/listing-observations-in-group/
> >
> > Although understanding the principles there will do no harm, my guess
> > is that you don't need it given -egen-'s -mode().
> >
> > Nick
> > njcoxstata@gmail.com
> >
> >
> > On 22 April 2013 11:26, Estrella Gomez <estrellastata@gmail.com> wrote:
> >
> > > I am cleanning a music dataset and one of the problems I have is that
> > > there are many cases in which there two different origin countries for
> > > the same artist. For instance, Shakira appears as from USA, Colombia,
> > > Netherlands and UK.
> > >
> > > I want to assign one unique origin country to each artist based on the
> > > number of records. I have 94,330,173 observations, so I can't do it
> > > manually.
> > >
> > > My problem is that I don't know how to tell Stata that I want to see
> > > those cases in which there are different countries for the same
> > > artist. Both are string variables. Once I identify those
> > > "wrong"observations,  I would select one unique country for each
> > > artist according to the number of Total sales, which is numerical
> > > variable
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