Here's one in two lines:
bysort hhid (period): gen tempvar = sum(switch)
bysort hhid tempvar: gen myduration = _N
-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Winter
Sent: Thursday, April 06, 2006 4:14 PM
To: statalist@hsphsun2.harvard.edu
Subject: RE: st: RE: How to construct a duration variable?
Good point. Drat.
At 04:05 PM 4/6/2006, you wrote:
>Not so. Each person can have one or more
>spells on each -Brand-. Your code lumps
>them all together.
>
>Nick
>n.j.cox@durham.ac.uk
>
>Nick Winter
>
> > I think
> >
> > bysort hhid Brand: gen Duration=_N
> >
> > should do it.
> >
> > --Nick Winter
> >
> > At 01:42 PM 4/6/2006, you wrote:
> > >Thank you, Nick.
> > >
> > >For example, there are three brands in the market: A, B and C.
One
> > >consumer buy A at the first period. At the second period, she
> > >switches to B. Since then, she keeps buying B for the next four
> > >periods. After that, she switches to C etc.
> > >
> > >Then the duration variable I want should be:
> > >
> > >hhid Period Brand Switch Duration
> > >1 1 A 0 1
> > >1 2 B 1 4
> > >1 3 B 0 4
> > >1 4 B 0 4
> > >1 5 B 0 4
> > >1 6 C 1 2
> > >1 7 C 0 2
> > >1 8 A 1 1
> > >1 9 B 1 4
> > >1 10 B 0 4
> > >1 11 B 0 4
> > >1 12 B 0 4
> > >1 13 C 1 2
> > >1 14 C 0 2
> > >
> > >I wish that it's clear this time. I just not sure how to construct
> > >the duration variable in Stata.
>
>
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________________________________________________________
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Assistant Professor 607.255.4530 f
Department of Government nw53@cornell.edu e
Cornell University falcon.arts.cornell.edu/nw53 w
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Ithaca, NY 14853-4601
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