# Re: st: benchmarking + determine the peers

 From "Eva Poen" <[email protected]> To [email protected] Subject Re: st: benchmarking + determine the peers Date Tue, 30 Sep 2008 15:41:49 +0100

```You posted exactly the same question on Saturday, and I replied. If
you still have problems, tells us where exactly.

Eva

2008/9/30 Bastian Steingros <[email protected]>:
> Dear Stata users,
>
> I am searching a function in stata to program peer groups.
> In my benchmarking study about American industries I want to compare companies by its sales, earnings etc.
> I use the three digit industry code to classify the industries (sic-codes). The peer group must be within the same industry.
> Here, the purpose is to compute the mean or median of the sales and to see if the respective firm's performance  is below or above the mean or the median.
>
> But, the peer group of firm X contains all the companies with the same digit code but *not* firm X (otherwise I would compare X with itself)
>
> To conclude:
>
> year   sic-code firm  sales mean median
> 1990   333         X      10     ?         ?
> 1990   333         Y      20     ?         ?
> 1990   333         Z      30     ?         ?
> ---------------------------------------------
> 1990   334         A      21     ?         ?
> 1990   334         B       5      ?        ?
> ---------------------------------------------
> 1991   etc. ...
>
> so, in 1990
> the peer group mean/median for X must contain (20+30)  but not 10
> the peer group mean/median for Y must contain (10+30)  but not 20
> the peer group mean/median for Z must contain (10+20)  but not 30
> and so on...
>
> is there a way to program is stata something like:
>
> by year sic-code, sort: egen median/mean *without the sales of the firm X / firm Y etc.*
>
> (Please note, it is basically more important for me to obtain the *median* than the mean peer group due to the outlier problem of the mean function.)
>
>