Re: st: filling in the gaps

[Jan Ditzen <jan@ditzen.net>]

Sorry, I was not aware of the missing years. Instead of only adding a 
one, calculate the difference between the years and add it to the grade 
the school year before:

by id (sch_year), sort: replace grade = 
grade[_n-1]+sch_year-sch_year[_n-1] if grade == .

Best wishes,
Jan

Am 18.01.2013 09:44, schrieb Jan Ditzen:
> Good morning,
> if I understood your problem correctly the following should help:
>
> by id (sch_year), sort: replace grade = grade[_n-1]+1 if grade == .
>
> "by id (sch_year), sort:" makes sure that the data gets sorted in the 
> correct way, i.e. by individuals (id) and then by school year. 
> Secondly the by command makes sure that the command behind the colon 
> is repeated for each group. If grade is missing (if grade == .) then 
> the value is replaced by the preceding value (grade[_n-1]) added with 
> one. I think the only problem which might occur is if pupils repeat a 
> year.
>
> Maybe there is a better solution but I think this should work.
>
> All the best,
>
> Jan
> Am 18.01.2013 09:21, schrieb John Singhammer:
> > Dear statalister
> >
> > I'm working on a dataset consisting of information on 45.000 school 
> > children
> > Data has been collected annually since 2009, though not for all children
> >
> > Information on grade has been imported from a national register.
> > However, that information is only available up to the year 2011
> >
> > Consequently, information on grade is missing for the year 2012 and 2013
> >
> > The data look like this:
> >
> > id    sch_year    grade
> > 347246    2010    2
> > 347246    2011    3
> > 347246    2012    .
> > 731909    2010    4
> > 731909    2011    5
> > 731909    2012    .
> > 901302    2011    4
> > 901302    2013    .
> >
> >
> > How do I fill in the blanks?... and how do I take care of the cases
> > where information is missing for an entire year (eg. id 901302)?
> >
> > Note: A school year is calculated as beginning in august  and ending
> > in june the next year. Thus, the year 2011 begins august 2010 and ends
> > in june 2011.
> >
> >
> > Any advices would be much appreciated.
> >
> > Thanks.
> > John Singhammer
> > University of Southern Denmark
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