Re: st: RE: Creating missing data

[Keith Dear <keith.dear@anu.edu.au>]

But celdjt said he wanted to do this for every fifth *multiple-record* 
case. He could first drop the single-record cases, apply Nick's code, then 
append them back. Or is there a neater way?
kd

At 12:18 PM 4/11/04, you wrote:

> Suppose your identifiers run 1, 2, ... . If this isn't true,
>
> . egen id = group(whateverisyourid)
>
> will make it so.
>
> Now, if I understand you correctly, you want to
>
> . bysort id (entrytime):
>         replace somevar = . if _n == 1 & mod(id,5) == 0
>
> Nick
> n.j.cox@durham.ac.uk
>
> celdjt@umich.edu
>
> > My
> > question is about making an adjustment to the surrogate data set. The
> > surrogate data set contains about 3500 cases, some of which
> > have just one
> > record per case, and others have multiple records. Each record has a
> > variable recording an entering time and an exit time for that record.
> > Hence, single record cases have one entry time and one exit
> > time; multiple
> > record cases have multiple entry and multiple exit times. I
> > would like to
> > convert the first entry time for every fifth multiple-record
> > case in this
> > data set into a missing value. Are there any suggestions for
> > how this might be done.
>
> *
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==========================================================
Dr Keith B.G. Dear
Senior Fellow
* Centre for Mental Health Research (CMHR)
* National Centre for Epidemiology and Popn Health (NCEPH)

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