Re: st: loops for regions

[Chiara Mussida <cmussida@gmail.com>]

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:
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>>> *   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)
>> *
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>> *   http://www.ats.ucla.edu/stat/stata/
> *
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>


-- 
Chiara Mussida
PhD candidate
Doctoral school of Economic Policy
Catholic University, Piacenza (Italy)

*
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