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From |
Michael Betz <betz.40@buckeyemail.osu.edu> |

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

Subject |
st: Creating dummy variables |

Date |
Wed, 16 Nov 2011 02:44:50 +0000 |

Hi all, I have two categorical variables "fips1" and "fips2" that record the US county of the observation. For each "fips1" there are many "fips2" counties as below fips1 fips2 1001 1073 1001 1021 1001 1101 1003 12031 1003 1099 I need to create dummy variables for each county in "fips1" and "fips2" and then create variables representing the difference between the two dummy variables as below: fips1 fips2 dum1_1 dum1_2 dum2_1 dum2_2 dum2_3 dum2_4 1_1-2_1 1_1-2_2 1_1-2_3 1001 1003 1 0 1 0 0 0 0 1 1 1001 1021 1 0 0 1 0 0 1 0 1 1001 1101 1 0 0 0 1 0 1 1 0 1003 1021 0 1 0 1 0 0 0 0 0 1003 1001 0 1 0 0 0 1 0 0 0 One added constraint is that each of "fips1" and "fips2" creates 3,000 dummies, so Stata cannot hold variables representing the difference between all pairs of dummy variables. I need to only calculate the difference in dummies for the pairs that in the data (i.e. according to the example above I would not need the difference between the dummies for "fips1"=1001 and "fips2"=1001 because that pair doesn't exist in my data) I've been thinking all day trying to come up with a solution, but to no avail. I appreciate and help or suggestions. Thanks, Mike * * 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/

**Follow-Ups**:**Re: st: Creating dummy variables***From:*Matthew White <mwhite@poverty-action.org>

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