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Re: st: RE: Problem with generating time dummies in panel data

From   "Daghan Yeldan" <>
Subject   Re: st: RE: Problem with generating time dummies in panel data
Date   Mon, 17 Jul 2006 16:10:26 +0200

Thanks Ada,
But tab year if ~mi(minder), gen(minder)
makes my minder values 0 for all the id (resp96)numbers. I am wondering if I can generate these dummies for each with a command which captures the id number and the year as well. Dropping missing values wont help as well than I get no observation warning. I am quite new with Stata and I think what I am looking forward to create has to capture the id numbers and years both otherwise it is useless. Until now the advices I get generate things which are almost the same and were dropped when they put them in a regression.
Moreover, when I try to implement the advices of the user (I thank them for their attendance my problem) generates 0 for the other years although there is no observations are present. This is the problem I am trying to solve for days.

best wishes,

From: "Ada Ma" <>
Subject: Re: st: RE: Problem with generating time dummies in panel data
Date: Mon, 17 Jul 2006 14:42:39 +0100

You have to tell Stata that you don't want a value generated if minder
is missing.  Your command refers to the year variable, not the minder
variable although the generated variables are named minder1, minder2,
minder3, you could have called the three dummy variables holiday1,
holiday2, holiday3, if you have written -tab year, gen(holiday)-

Therefore if you want no dummies generated when minder is missing you
should write:

tab year if ~mi(minder), gen(minder)

Or you can restrict your regression to use only obs that has a minder
value.  Or you can drop all obs that has got a missing minder value.

On 7/17/06, Daghan Yeldan <> wrote:
Thank you at least I get the year dummies, but again I am facing with a
Namely, the variable minder is defined as hp<h and gets the value 1 if this
is the case, gets value 0 if this is not the case for each year. Now when I
list the variables I see value 0 is attached to a year even if there is no
minder value associated with the year. For example
| resp96 y minder minder1 minder2 minder3 |
1. | 701 1994 0 1 0 0 |
2. | 701 1996 1 0 1 0 |
3. | 1602 1994 . 1 0 0 |
4. | 1602 1996 . 0 1 0 |
5. | 1602 1998 . 0 0 1 |

For resp96 1602, there is no minder variable present, but if you look at the
dummies there are values attached to them.
If I use them in a regression, then I get muticollinearity and automatically
dropped by stata.
My excuses for the inconvienient results but I am stucked with this problem
by days.

Thank you in advance,

>From: "Scott Merryman" <>
>To: <>
>Subject: RE: st: RE: Problem with generating time dummies in panel data
>Date: Mon, 17 Jul 2006 08:19:45 -0500
>For year dummies I would try -tab year, gen(minder)-
>This will create three dummies callers (named minder1, minder2, minder3
>corresponding to years 1994, 1996, and 1998).
> > -----Original Message-----
> > From: [mailto:owner-
> >] On Behalf Of Daghan Yeldan
> > Sent: Monday, July 17, 2006 8:15 AM
> > To:
> > Subject: RE: st: RE: Problem with generating time dummies in panel data
> >
> > thnx for the advice. But I tried them all before I sent this message.
> > problem I get is when I do this,
> >
> > tab minder,g(min) it only creates two dummies instead of 3. I have 3
> > of variables.
> > How can I solve this problem?
> > cheers,
> > d
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