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From |
Chiara Mussida <cmussida@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: loops for regions |

Date |
Thu, 6 Sep 2012 16:26:41 +0200 |

Thanks Nick. I will test your suggestion in Stata, since I'm not too confident with mata. On 06/09/2012, Nick Cox <njcoxstata@gmail.com> wrote: > Thanks. A quick stab at this is that you have two vectors x1 and x2 and go > > . mata : > ------------------------------------------------- mata (type end to > exit) ----------------------------------------- > : > : x1 = (10,10,10,10,10) > > : x2 = (12,14,16,18,20) > > : sum_x1 = sum(x1) > > : sum_x2 = sum(x2) > > : a = x2 / sum_x2 > > : b = (log(x2) - log(x1)) :- (log(sum_x2) - log(sum_x1)) > > : sqrt(sum(a :* (b:^2))) > .1763637091 > > : end > > The main thing is not whether I have understood the details but that > this is a calculator problem; it is just more convenient for a Stata > user to use Mata for a calculator. > > In Stata it could be something like (completely untested code) > > sum x1, meanonly > local sum_x1 = r(sum) > sum x2, meanonly > local sum_x2 = r(sum) > > gen work = x2 / `sum_x2' > replace work = work * (((log(x2) - log(x1)) - (log(`sum_x2') - > log(`sum_x1'))) > su work, meanonly > di sqrt(r(sum)) > > Nick > > On Thu, Sep 6, 2012 at 8:05 AM, Chiara Mussida <cmussida@gmail.com> wrote: >> The reference is : >> D.M. Lilien, Sectoral shifts and cyclical unemployment, Journal of >> Political Economy, 90 (4) (1982), pp. 777–793. >> >> The index is defined on page 787. It is a bit more complicated than >> the herfindahl index. >> >> >> >> On 06/09/2012, Nick Cox <njcoxstata@gmail.com> wrote: >>> Did you try >>> >>> findit lilien >>> >>> Someone may recognise this, but you give no reference or definition. >>> >>> Nick >>> >>> On Wed, Sep 5, 2012 at 9:52 PM, Chiara Mussida <cmussida@gmail.com> >>> wrote: >>>> tried to write my own file since the next step will be, as i hope, to >>>> compute a Lilien index for each region. I tried to search for a stata >>>> program but i did not succeed. Does anybody know whether it exists? >>>> Thanks >>>> >>>> On 05/09/2012, Nick Cox <njcoxstata@gmail.com> wrote: >>>>> The first line confuses the -if- command and the -if- qualifier. >>>>> >>>>> I didn't look in detail at later code, as there should be no need to >>>>> write your own code, as many programs exist. -search inequality- for a >>>>> start. See also e.g. -ineq- (SSC), -hhi- (SSC). >>>>> >>>>> In fact, in many ways this is a calculator problem easily tackled with >>>>> Mata. >>>>> >>>>> . mata >>>>> : freq = (0, 0, 3, 9, 9) >>>>> : pr = freq :/ sum(freq) >>>>> : sum(pr:^2) >>>>> .387755102 >>>>> >>>>> In fact, zero frequencies map to zero squared proportions and can be >>>>> omitted. >>>>> >>>>> This index, although often attributed to Herfindahl by economists who >>>>> know only their only literature, was in essence invented decades >>>>> before by Gini. I don't have the reference in my head, but I think it >>>>> is in Bishop, Y., Fienberg, S.E. and Holland, P.W. 1975. Discrete >>>>> multivariate analysis. Cambridge, MA: MIT Press. Please trump me by >>>>> providing a yet earlier reference. >>>>> >>>>> Nick >>>>> >>>>> On Wed, Sep 5, 2012 at 5:15 PM, Chiara Mussida <cmussida@gmail.com> >>>>> wrote: >>>>> >>>>>> I want to generate a variable herf1 which takes the value of the >>>>>> below >>>>>> index for region 1, and thereafter repeat this loop for all the >>>>>> region >>>>>> in my dataset. The problem is that with the below command I get the >>>>>> herf1 index for region 1, which is identycal in value (I tried) to >>>>>> the >>>>>> herf2 for region2 whether I repeat this llop for region2, by starting >>>>>> with "if reg==2, and so forward for all the regions. >>>>>> >>>>>> if reg==1 { >>>>>> tab cat12_2, gen(categ) >>>>>> forvalues k = 1 2 to 12 { >>>>>> sum categ`k', meanonly >>>>>> gen share`k'=r(mean) if reg==1 /*shares of each occ cat on >>>>>> the >>>>>> total >>>>>> occupation, time t*/ >>>>>> } >>>>>> } >>>>>> >>>>>> gen herf1=(share1)^2 + (share2)^2 + (share3)^2 + (share4)^2 + >>>>>> (share5)^2 + (share6)^2 + (share7)^2 + (share8)^2 /// >>>>>> + (share9)^2 + (share10)^2 + (share11)^2 + (share12)^2 /*Herfindhal >>>>>> Index Region1*/ >>>>>> the variable reg takes 1 for region1, 2 for region2...up to 20 for >>>>>> region20. In other words, Stata does not compute the specific index >>>>>> for each region, but the same index region by region. > > * > * 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/ > -- Chiara Mussida PhD candidate Doctoral school of Economic Policy Catholic University, Piacenza (Italy) * * 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: loops for regions***From:*Nick Cox <njcoxstata@gmail.com>

**References**:**st: loops for regions***From:*Chiara Mussida <cmussida@gmail.com>

**Re: st: loops for regions***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: loops for regions***From:*Chiara Mussida <cmussida@gmail.com>

**Re: st: loops for regions***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: loops for regions***From:*Chiara Mussida <cmussida@gmail.com>

**Re: st: loops for regions***From:*Nick Cox <njcoxstata@gmail.com>

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