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RE: st: Cannot generate a dummy variable using if command
From
Joseph Kwan <[email protected]>
To
"[email protected]" <[email protected]>
Subject
RE: st: Cannot generate a dummy variable using if command
Date
Fri, 2 Aug 2013 18:26:52 +0000
Thanks Sergiy and Joe. I just tried and it worked. I get it now. It is a relief to know there is nothing wrong with the program :)
Joseph
________________________________________
From: [email protected] [[email protected]] on behalf of Joe Canner [[email protected]]
Sent: Friday, August 02, 2013 7:21 PM
To: [email protected]
Subject: RE: st: Cannot generate a dummy variable using if command
To elaborate a bit on what Sergiy said...
The reason you need to add "!missing(age)" (or similar) to your statement is that a missing value is the largest value there is (i.e., the highest number possible for that data type, plus one). Thus, a missing value for age will always satisfy the condition "if age>25"
This is in contrast to SAS, for example, where missing values are the lowest value there is (i.e., the lowest number possible minus one).
Regards,
Joe
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Sergiy Radyakin
Sent: Friday, August 02, 2013 2:14 PM
To: [email protected]
Subject: Re: st: Cannot generate a dummy variable using if command
There is nothing wrong.
Type summarize age and look at the min age reported.
A simpler and more robust version is something like:
gen old=age>25 if !missing(age)
Finally note that in nlsw88 dataset (if you are using it) there are no individuals younger than 34.
Best, Sergiy
On Fri, Aug 2, 2013 at 2:05 PM, Joseph Kwan <[email protected]> wrote:
> I would like to generate a variable for people older than 25 years
> old,
>
> so I use
>
> gen old=1 if age>25
>
> but then Stata returns with an old dummy variable with all 1 for all observations.
>
> I checked the syntax and I do not know what is wrong.
>
> Is Stata known to have faults like that?
>
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