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Re: st: How to generate lags where each variable to be lagged has multiple values in the previous time periods


From   Nick Cox <njcoxstata@gmail.com>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   Re: st: How to generate lags where each variable to be lagged has multiple values in the previous time periods
Date   Mon, 29 Apr 2013 23:08:10 +0100

See the FAQ

http://www.stata.com/support/faqs/data-management/repeated-time-values/index.html

or try

isid school grade year
duplicates list school grade year

(Your variable names, naturally.)
Nick
njcoxstata@gmail.com


On 29 April 2013 22:51, Stuart Buck <stuartbuck@gmail.com> wrote:
> This looks good, except that for any of the tsset commands, I get the
> error code 451: "repeated time values within panel."
>
> On Mon, Apr 29, 2013 at 4:05 PM, Nick Cox <njcoxstata@gmail.com> wrote:
>> Treating each school separately is just a twist on this:
>>
>> gen cohort = year - grade
>> egen id = group(school cohort), label
>> tsset id year
>>
>>
>> Nick
>> njcoxstata@gmail.com
>>
>>
>> On 29 April 2013 20:32, Nick Cox <njcoxstata@gmail.com> wrote:
>>> Focus on any cohort, say the cohort that was grade 8 in 2011, grade 7
>>> in 2010 and so forth. Evidently, the difference (year - grade) is
>>> constant, and therefore an identifier, for that cohort. Thus after
>>>
>>> gen id = year - grade
>>>
>>> either
>>>
>>> tsset id year
>>>
>>> or
>>>
>>> tsset id grade
>>>
>>> defines a panel dataset with an identifier and a time variable and
>>> time series operators can then be applied.
>>>
>>> Nick
>>> njcoxstata@gmail.com
>>>
>>> On 29 April 2013 19:46, Stuart Buck <stuartbuck@gmail.com> wrote:
>>>
>>>> Passage rates for all Texas schools for 2008, 2009, 2010, and 2011 --
>>>> this is important -- by grade. So each row in the dataset is School,
>>>> Year, Grade, and then scores (plus other demographic variables, etc.).
>>>>
>>>> In other words, the dataset looks like this:
>>>>
>>>> Year     SchoolID     Grade     TestScore
>>>> 2011    1                  6               ***
>>>> 2011     1                 7               ***
>>>> 2011     1                 8               ***
>>>>
>>>> And so on and so forth -- multiple grades in each school in each year.
>>>>
>>>> Here's what I want:
>>>>
>>>> To be able to regress any given school's performance in Grade X in
>>>> Year T on, among other things, how that same school did with the same
>>>> cohort of kids in the previous grade (Grade X-1) in the previous year
>>>> (Year T-1). I.e., if a middle school's Grade 8 passage rate in 2011 is
>>>> the outcome, I'd like to be able to control for that same school's
>>>> Grade 7 passage rate in 2010, thus giving a somewhat crude measure of
>>>> how much that group of kids progressed since the previous year.
>>>>
>>>> How would I generate an all-purpose lagged TestScore variable for all
>>>> the schools in the dataset, lagging by both year and grade at once?
>>>> All the Stata instructional material I see on lagged variables just
>>>> lags based on time, not on both time and some other variable too
>>>> (grade).
>> *
>> *   For searches and help try:
>> *   http://www.stata.com/help.cgi?search
>> *   http://www.stata.com/support/faqs/resources/statalist-faq/
>> *   http://www.ats.ucla.edu/stat/stata/
>
>
>
> --
> Stuart Buck
> http://about.me/stuartbuck
> 479-200-2750 (cell)
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/faqs/resources/statalist-faq/
> *   http://www.ats.ucla.edu/stat/stata/
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/


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