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From |
Cameron Hooper <chooper@umich.edu> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Programing "by" and creating a new dataset |

Date |
Thu, 10 Mar 2005 09:08:41 -0500 |

Hi Ichiro Thanks very much for your help. I've had a look at -byable- as suggested. Having your code as a guide to its use will make it much easier to see how to implement this command. Cheers Cameron Ichiro Fujikake wrote: > Hi Cameron, > > Following is a byable and with newfile() option version of your program, I > hope. Please refer to byable and syntax entries of Programming manual and > -help levels- for information on what I added. > > Ichiro > > =*=*=*= > capture program drop kpmetric > qui program kpmetric , byable(onecall) > version 8 > syntax , newfile(string) > local by "`_byvars'" > tempvar chng > generate `chng' = sign(x2 - x1) > > tempvar gr > if _by()==1 { > qui egen `gr'=group(`by') > } > else { > qui gen `gr'=1 > } > qui levels `gr', local(list) > foreach X of local list { > preserve > qui keep if `gr'==`X' > qui count > local n = r(N) > local n1 = r(N) - 1 > local p = 0 > > forvalues i =1/`n1' { > local k = `i' + 1 > forvalues j = `k'/`n' { > local opposite = `chng'[`i'] * `chng'[`j'] < 0 > local flip = sign(x1[`i'] - x1[`j']) != sign(x2[`i'] - > x2[`j']) > local diverge = abs(x2[`i'] - x2[`j']) > abs(x1[`i'] - > x1[`j']) > > if `opposite' & (`flip' | `diverge') { > local p = `p' + 1 > } > } > } > > local p_`X' = `p'/comb(`n',2) > local n_`X'=`n' > restore > } > preserve > qui { > keep `by' `gr' > if _by()==1 { > bysort `by' : keep if _n==1 > } > else { > keep if _n==1 > } > gen p=. > gen n=. > foreach X of local list { > replace p=`p_`X'' if `gr'==`X' > replace n=`n_`X'' if `gr'==`X' > } > } > drop `gr' > save `newfile' > restore > end > > =*=*=*= > > On 05.3.10 6:41, "Cameron Hooper" <chooper@umich.edu> wrote: > > >>Consider the following data: >> >>. use http://www-personal.umich.edu/~chooper/stata/kptest1 >>. list >> >> +---------------------+ >> | id year x1 x2 | >> |---------------------| >> 1. | 1 1990 10 8 | >> 2. | 1 1990 7 11 | >> 3. | 1 1990 6 4 | >> 4. | 1 1990 9 12 | >> 5. | 1 1990 8 6 | >> +---------------------+ >>. >> >>I want to create a new variable based on the pairwise comparisons of >>-sign(x2 - x1)-. (I've included a brief explanation of these comparison >>as a postscript to this post. I don't think it is necessary to read it >>to understand my question.) >> >>To achieve this I've written the following program. I don't think it is >>important to follow the code inside the -forvalues- loop. >> >>------------------------------------- >> >>capture program drop kpmetric >>program kpmetric , rclass >>version 8 >>tempvar chng >>generate `chng' = sign(x2 - x1) >>qui count >>local n = r(N) >>local n1 = r(N) - 1 >>local p = 0 >> >>forvalues i =1/`n1' { >> local k = `i' + 1 >> forvalues j = `k'/`n' { >> >> local opposite = `chng'[`i'] != `chng'[`j'] & \\\ >> `chng'[`i'] != 0 & `chng'[`j'] != 0 >> local flip = sign(x1[`i'] - x1[`j']) != sign(x2[`i'] - x2[`j']) >> local diverge = abs(x2[`i'] - x2[`j']) > abs(x1[`i'] - x1[`j']) >> >> if `opposite' & (`flip' | `diverge') { >> local p = `p' + 1 >> } >> } >>} >> >>local p = `p'/comb(`n',2) >>return scalar p = `p' >>end >> >>-------------------------------------------------------------------------- >>Here as a sample run: >> >>. use http://www-personal.umich.edu/~chooper/stata/kptest1 >>. kpmetric >>. return list >> >>scalars: >> r(p) = .6 >> >> >>In practice my data is more complex. I have multiple years and companies >>so I need to make my program understand the -by- prefix. I also need a >>way of capturing the results of the program. This is what I would want >>to achieve: >> >>. use http://www-personal.umich.edu/~chooper/stata/kptest2 >>. sort id year >>. list >> >> +---------------------+ >> | id year x1 x2 | >> |---------------------| >> 1. | 1 1990 10 8 | >> 2. | 1 1990 7 11 | >> 3. | 1 1990 6 4 | >> 4. | 1 1990 9 12 | >> 5. | 1 1990 8 6 | >> |---------------------| >> 6. | 1 1991 5 8 | >> 7. | 1 1991 7 9 | >> 8. | 1 1991 4 4 | >> 9. | 2 1988 2 6 | >> 10. | 2 1988 5 3 | >> |---------------------| >> 11. | 2 1988 9 7 | >> 12. | 2 1988 4 1 | >> 13. | 2 1989 7 7 | >> 14. | 2 1989 8 8 | >> 15. | 2 1989 3 3 | >> +---------------------+ >> >>. by id year: kpmetric >>. list >> >> id year p n >>1. 1 1990 0.60 5 >>2. 1 1991 0.00 3 >>3. 2 1988 0.33 4 >>4. 2 1989 0.00 3 >> >>Any suggestions on how I can achieve this? >> >>Thanks, >> >>Cameron >> >>PS. For those interested in what this code is trying to achieve here is >>a brief explanation. Consider the following data: >> >>analyst f1 f2 >> 1 10 12 >> 2 11 9 >> 3 8 10 >> >>This represents the forecasts of three analysts. f1 is forecast at time >>1 and f2 is the revised forecast at time 2, after the analysts' observe >>a publicly available signal. Define a measure of differential >>interpretations of the public signal to be the proportion of >>inconsistent revisions. Inconsistent revision move in opposite >>directions AND either flip or end up further apart they the original >>forecasts.For example, analyst 1 revised his forecast upwards (from 10 >>to 12) while analyst 2 revised her forecast downwards (11 to 9). Since >>the revisions are in opposite directions and cross they are defined as >>inconsistent. In contrast both analysts 1 and 3 revise their forecasts >>upwards and are thus consistent revisions. While analysts 2 and 3 revise >>in different directions, they are not inconsistent because they converge >>as a result of observing the common signal. Of the 3 analyst pairs only >>1 is inconsistent (1v2) so the value of the differential interpretations >>metrics equals 1/3 (#inconsistent pairs / total pairs). >> >>* >>* 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/ >> > > > > * > * 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/ > > -- Cameron Hooper <chooper@umich.edu> University of Michigan Business School 701 Tappan St., Ann Arbor, MI 48109 phone: 734-615-4178 fax: 734-936-0282 Public Key: http://wwwkeys.pgp.net:11371/pks/lookup?op=index&search=0xFCCF8C91 * * 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/

**References**:**Re: st: Programing "by" and creating a new dataset***From:*Ichiro Fujikake <fujikake@cc.miyazaki-u.ac.jp>

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