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From |
abasu@medicine.bsd.uchicago.edu |

To |
statalist@hsphsun2.harvard.edu |

Subject |
RE: st: question: how do i... |

Date |
Sun, 6 Mar 2005 22:40:19 -0600 |

global lst "A B C D" egen maxscore = rmax(votesA votesB votesC votesD) foreach i of global lst { gen diff`i'= maxscore - votes`i' replace diff`i'=. if diff`i'==0 } egen margin_of_victory = rmin(diffA diffB diffC diffD) Anirban -----Original Message----- From: Phil Schumm To: statalist@hsphsun2.harvard.edu Sent: 3/6/2005 8:54 PM Subject: Re: st: question: how do i... At 1:53 AM +0000 3/7/05, israel solaresbravo wrote: >i want to construct a variable called margin of victory: > >my data set looks something like this: > > >margin_of_victory> > >my question is: > >how do i create a variable called margin_of_victory = votes for 1st >place - votes for 2nd place?, i.e. 21-10 for state 1, 22 - 11 for >state 2, 13 - 12 for state 3, 4 - 3 for state 4, etc. If you reshape your data from wide to long form, then this is a snap. Here are your data: . li +-------------------------------------------+ | state votesa votesb votesc votesd | |-------------------------------------------| 1. | 1 10 1 6 21 | 2. | 2 11 2 7 22 | 3. | 3 12 3 8 13 | 4. | 4 1 4 2 3 | 5. | 5 2 5 3 7 | +-------------------------------------------+ Now, try the following (output omitted): . reshape long votes, i(state) j(candidate) string . bys state (votes): gen margin = votes[_N] - votes[_N-1] . reshape wide which produces exactly what you want: . li +----------------------------------------------------+ | state votesa votesb votesc votesd margin | |----------------------------------------------------| 1. | 1 10 1 6 21 11 | 2. | 2 11 2 7 22 11 | 3. | 3 12 3 8 13 1 | 4. | 4 1 4 2 3 1 | 5. | 5 2 5 3 7 2 | +----------------------------------------------------+ As you can see, the trick is in using -reshape-. If you're not familiar with what -reshape- does, use -list- after the first reshape and take a look, then read [R] reshape. Once the data are in long form, we sort by state and number of votes, and then within each state, compute the difference between the largest number of votes and the next largest (hint: _N refers to the total number of observations within the state, and votes[_N] is the last observation within the state (which, since the observations are sorted by number of votes, is the observation with the largest vote count)). -- Phil * * 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/ NOTICE OF CONFIDENTIALITY - This material is intended for the use of the individual or entity to which it is addressed, and may contain information that is privileged, confidential and exempt from disclosure under applicable laws. If the reader of this material is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. Please notify the sender of the error and destroy the Email you received. * * 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**:**RE: st: question: how do i...***From:*Keith Dear <keith.dear@anu.edu.au>

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