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.)
>
> So, please help me find a solution to the median peer group first.
>
> Many thanks in advance!
>
> Bastian
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