Re: st: filling in the gaps

[Jan Ditzen <jan@ditzen.net>]

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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