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From |
Nick Cox <njcoxstata@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: loops for regions |

Date |
Thu, 6 Sep 2012 09:20:47 +0100 |

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/

**Follow-Ups**:**Re: st: loops for regions***From:*Chiara Mussida <cmussida@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>

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