Re: st: use of expand

[Roger Newson <roger.newson@kcl.ac.uk>]

At 10:28 27/04/04 +0100, Ann Fitzmaurice wrote:
> Good morning
>
> i have a data set with four variables, year ca age and n, where n is the 
> number of each combination or the other three
> e.g.
>
> yeat    ca      age     n
> 1995    1       13      309
> 1995    1       14      420
> 1995    2       13      363
>
> the years can range from 1995-2002, ca from 1-6 and age from 13-19
>
> what i would like to do is to expand the data set that i have one line for 
> each case so for the first line above i would have 309 duplicated lines
>
> i have try using expand but it does not give me the data set i want (i 
> know the total n when expanded)
As Nick Cox says, Ann doesn't specify exactly what is going wrong. However, 
I realise that -expand- can be confusing in that it puts the new 
observations at the end of the dataset, when the user usually wanted them 
to be next to the observations from which they were copied. Ann might like 
to try the -expgen- package, downloadable from SSC, which is a more 
user-friendly version of -expand-. In Stata, type

ssc desc expgen

or

findit expgen

to find out more.

I hope this helps.

Roger


--
Roger Newson
Lecturer in Medical Statistics
Department of Public Health Sciences
King's College London
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Opinions expressed are those of the author, not the institution.

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