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Re: st: weights in pooled repeated cross sections


From   Fernando Rios Avila <f.rios.a@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: weights in pooled repeated cross sections
Date   Tue, 27 Sep 2011 17:47:03 -0400

Steve
I understand. Thanks for the advice and clarification.
Fernando

On Tue, Sep 27, 2011 at 5:40 PM, Steven Samuels <sjsamuels@gmail.com> wrote:
>
> Fernando-
>
> If, say, 90 PSUs repeated over four years, an analysis which ignored this would count them as 360 PSUs. The consequence would be standard errors and p-values that are too small.
>
> By the way, I have ignored this issue in past posts to Statalist,  which recommended that "years" could (always) be crossed with the original strata to form new super-strata.  I apologize for this incorrect advice.
>
> Steve
>
>
>
>
> On Sep 27, 2011, at 4:37 PM, Fernando Rios Avila wrote:
>
> Hi Steven,
> Since it seems you have experience with this kind of data, i wonder if
> you know if there is any particular consequence of pooling and using
> the weights as you mention when each individual survey is not
> statistically independent from each other, meaning that some Primary
> sample units may appear more than once through the different surveys,
> while others wont.
> Thanks!
>
> On Tue, Sep 27, 2011 at 4:35 PM, Nick Cox <njcoxstata@gmail.com> wrote:
>> PSUs are primary survey units.
>>
>> Nick
>>
>> On Tue, Sep 27, 2011 at 9:32 PM, Steven Samuels <sjsamuels@gmail.com> wrote:
>>>
>>> 1. Pool
>>> 2. Divide weights by four (would affect only totals, but still a good idea)
>>> 3. -svyset- the whole thing.
>>>
>>>
>>> Steve
>>>
>>> On Sep 27, 2011, at 10:40 AM, Ivica Rubil wrote:
>>>
>>> so, you're saying I just pool the 4 datasets, divide the weights by 4,
>>> and apply -svyset- to the pooled dataset? Or should I rather use
>>> -svyset- for each of the 4 datasets, pool them in one, and then divide
>>> the weights by 4?
>>> Further, sorry for bothering you: what are PSUs? How do I check if they
>>> change form year to year?
>>>
>>> --
>>> Ivica Rubil
>>> Ekonomski institut / The Institute of Economics, Zagreb
>>> Trg J. F. Kennedyja 7, 10 000 Zagreb, Croatia
>>> tel. +385-1-2362-269
>>> fax. +385-1-2335-165
>>> irubil@eizg.hr
>>> www.eizg.hr
>>>
>>>
>>> -----Original Message-----
>>> From: owner-statalist@hsphsun2.harvard.edu
>>> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Steven
>>> Samuels
>>> Sent: 27. rujan 2011 15:51
>>> To: statalist@hsphsun2.harvard.edu
>>> Subject: Re: st: weights in pooled repeated cross sections
>>>
>>>
>>> Ivica-
>>> You can use the individual weights, Ivica, but divide by 4 so that they
>>> sum to the average population total over the four years
>>>
>>> You still have to write the rest of the -svyset- command.  If the PSUs
>>> did not change over the four years, then treat the pooled sample as one
>>> large sample, and use the same -svyset- statement that you would use for
>>> a single year.  If some PSUs changed you will have to do some stratum
>>> recoding. For an example see
>>> http://www.cdc.gov/nchs/ppt/nchs2010/46_Moriarity.ppt
>>>
>>> Steve
>>>
>>> On Sep 26, 2011, at 12:03 PM, Ivica Rubil wrote:
>>>
>>> Dear all,
>>>
>>> I am trying to pool four repeated cross-sections of Croatian Hpusehold
>>> Budget Survey.
>>> For each year that I want to pool, I have sampling weights for each
>>> observation (both household and person).
>>> My questions are: What should I do with the weights once I pool the four
>>> datasets? Is it wrong to use
>>> dataset-specific weights in the pooled dataset and just run estimation
>>> commands with the weight option, if
>>> available? I am confused. Please, help.
>>>
>>
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