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From |
"Yi, Bingsheng" <byi@coba.usf.edu> |

To |
"'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu> |

Subject |
st: new expression: how to generate groups based on some characteristics, and assign a sample into the correct group |

Date |
Fri, 21 Jun 2002 11:57:10 -0400 |

Dear Statalister, I have sent my problem before, which I didn't express clearly, and therefore haven't received any reply. This time I express it more clearly, and I hope that you will help me out with the following problem. Let me express my sincerest thanks to you in advance!!! I need to assign a firm into an industry which should contain at least 10 firms, and a firm should belong to an industry with the most number of digits of industry code, so long as that industry contains at least 10 firms. If an industry has a code as 10, then it should contain all the firms with the same 2-digit industry code as 10. ind1`i' is the i-digit industry code, i=1,2,3,4. For example, ind4 is the 4-digit industry code. There are only one firm in industry 1028, industry 102, but 12 firms in industry 10, so the final industy code for firm 12 will be 10, and industry 10 should contain all the firms with ind2=10. The industry code for the first 10 firms is 1041,not 104,10, nor 1 since industry 1041 already contains 10 firms, even though industry 104,10,or 1 contain more than 10 firms. ind3grp contains all the firms with the same 3-digit industry code. obs q ind4 ind3 ind2 ind1 industry size ind4grp ind3grp ind2grp ind1grp 1 1041 104 10 1 1041 1 small ? ? 2 1041 104 10 1 1041 3 small ? ? 3 1041 104 10 1 1041 2 small ? ? 4 1041 104 10 1 1041 5 middle ? ? 5 1041 104 10 1 1041 4 middle ? ? 6 1041 104 10 1 1041 9 large ? ? 7 1041 104 10 1 1041 8 middle ? ? 8 1041 104 10 1 1041 11 large ? ? 9 1041 104 10 1 1041 10 large ? ? 10 1041 104 10 1 1041 7 middle ? ? 11 1044 104 10 1 104 6 N.A. ? ? 12 1028 102 10 1 10 18 N.A. N.A. ? . . Subsequently I will subdivide firms in each industry into small, middel and large groups according to firm size. The small group contains the smallest 30% firms in size within an industry, the middle group contains the middle 40% firms in size (30% to 70%), and the large group includes firms whose size belongs to the largest 30% in that industry. How I can subdivide firms according to size in an industry and assign a firm to a group according to its size? I also need to get the median or mean value of q for each of these groups within an industry. Take firm 1 as an example, its ind4 is 1041, and there are already 10 firms with ind4 as 1041, so firm 1 should be in industry 1041. According to its size, it belongs to samll group in industry 1041. Firm 1's industry-size adjusted q = firm 1's q - the mean q of small group under industry 1041. As to firm 11, first I need to assign firm 11 into industry 104 which contains all the firms with the same 3-digit industry code as 104, then I need to assign firm 11 into a group under industry 104 according to its size (a firm may belong to different groups under different industry codes), then I have to get the mean value of q of firms in the same group as firm 11. I hope that you will understand my problems now and help me out, I really apprecaite your great helps!!! Bing * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**st: RE: new expression: how to generate groups based on some characteristics, and assign a sample into the correct group***From:*"Nick Cox" <n.j.cox@durham.ac.uk>

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