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RE: st: RE: How to construct a duration variable?


From   "Nick Cox" <[email protected]>
To   <[email protected]>
Subject   RE: st: RE: How to construct a duration variable?
Date   Thu, 6 Apr 2006 21:05:43 +0100

Not so. Each person can have one or more
spells on each -Brand-. Your code lumps
them all together. 

Nick 
[email protected] 

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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