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From |
"Eva Poen" <eva.poen@gmail.com> |

To |
Statalist <statalist@hsphsun2.harvard.edu> |

Subject |
Re: st: benchmarking + determine the peers |

Date |
Sat, 27 Sep 2008 12:32:09 +0100 |

Bastian, there is an faq on this: "How do I create variables summarizing for each individual properties of the other members of a group? " which you can find here: http://www.stata.com/support/faqs/data/members.html . Your problem is similar to item 5: Specific problem: maximum age of the other children, but not exactly the same. This is how it could work: bysort siccode year: gen id = _n sum id gen median = . forvalues x = 1/`r(max)' { generate newsales = sales if id != `x' egen work = median(newsales), by(sic-code year) replace median = work if id == `x' drop work newsales } Means are easier to calculate; it's explained in the faq. Eva 2008/9/27 Bastian Steingros <Steingros@gmx.de>: > 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 * * 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/

**References**:**st: benchmarking + determine the peers***From:*"Bastian Steingros" <Steingros@gmx.de>

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