st: Adjusting overlapping spell data

[Birte Tiedemann <tiedemann@rheinahrcampus.de>]

Hello everybody,

I am working on a panel data set (spell type) with overlapping data on 
times of employment (ym):

id spellnr begindate enddate period unemployed
1 1 2008m4 2008m9 6 0
1 2 2009m3 2009m8 6 1
1 3 2009m9 2010m9 13 0
1 4 2010m3 2011m3 13 0
1 5 2009m7 2010m9 15 1
1 6 2011m1 2011m6 6 0

Now I'm trying to summarize times of employment and unemployment for 
every id whi.e avoiding double counting due to  overlappings. Also 
employment should be prioritised.

In the end the data is supposed to look like:
id spellnr begindate enddate period unemployed
1 1 2008m4 2008m9 6 0
1 2 2009m3 2009m8 6 1
1 3 2009m9 2010m9 13 0
1 4 2010m10 2011m3 6 0
1 6 2011m4 2011m6 3 0

I've no idea how to fix this in Stata. Hope you can help me. Thank you 
in advance.

Regards,
Birte

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