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st: RE: R: RE: add rows in order to balance the panel


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: R: RE: add rows in order to balance the panel
Date   Wed, 14 Feb 2007 22:17:38 -0000

-tsfill- is also worth noting. 

Nick 
n.j.cox@durham.ac.uk 

Sara Valentini
 
> Thank you very much Jose!

Romero, Jose Manuel
 
> Try the fillin command, this may help.

Sara Valentini

> I'm working with an unbalanced panel database. I would like to solve a
> simple problem, but I cannot figure out how to solve it. I try to
> explain my problem describing my data, it's easier!
> 
> My unit of analysis is customers (i). I observe these 
> customers for some
> quarters (t). The database has the following structure (more or less):
> 
> i   t  Y
> 
> 1  1  40
> 1  3  30
> 1  4  20
> 2  1  10
> 2  2  20
> 2  3  20
> 2  4  30
> 
> For simplicity, suppose I have only 4 quarters (t=1, 2, 3, 4) and two
> customers. This panel is unbalanced. As you can see, customer n. 1
> doesn't have information for quarter 2.
> 
> Y are the dollar spent but customers to buy some items.
> 
> I would like to add the following row to my database:
> 
> i  t  Y
> 
> 1  2  0

> That is, I would like to add the non purchase option. For example
> customer 1 does't buy anything at time 2, so I would like to 
> put a 0 in Y.
> 
> Specifically, I would like to find the way to add rows in my 
> database in
> order to have the same number of rows for each customers (4 in this
> example), rows with null values for some of the variables of the
> database (such as Y).
 
> I have a huge number of records so I cannot do that manually 
> J, or using
> excel or SPSS.
> 
> If you know a specific command to solve this problem, or have 
> an idea I
> appreciate any suggestion.
> 

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