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

 From "Daghan Yeldan" To statalist@hsphsun2.harvard.edu Subject Re: st: RE: Problem with generating time dummies in panel data Date Mon, 17 Jul 2006 17:37:40 +0200

I am using a first difference model where
&#8710;h= á94 min94+á96 min96+ á98 min98 + sex dummies+ age dummies

h= is the number of agreed working hours
hp=the number of desired working hours
minder= the difference between the number of desired working hours and number of agreed working hours.

My concern is to look for the differences in the á's during the time period.
&#8710;h is descirbed as Dh=h- h(_n-1) if y==y(_n-1)+2

As I mentioned earlier I am working with micro panel data and I appended the values in one dataset to run a regression. If I can manage to create these min dummies I will run an OLS and look for the effects at first place. But until, now I cannot create these dummies.

I think I inform you suffiecient about my struggle with generating the dummies.

Best Wishes,
d

```From: "Ada Ma" <heu034@googlemail.com>
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: RE: Problem with generating time dummies in panel data
Date: Mon, 17 Jul 2006 16:17:48 +0100

I think you need to clarify what kind of model you're trying to
estimate, the exact command and option you use to estimate the model,
plus some information on what h and hp are.

You shouldn't have get a "no observation" warning as the bits of data
you've posted clearly indicated that your "minder" variable carries
non missing values, that is unless you have severe missing values
problem in the other variables you're also using in your regression
model.

On 7/17/06, Daghan Yeldan <caracicatriz2002@hotmail.com> wrote:
```
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,
Daghan

>To: statalist@hsphsun2.harvard.edu
>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 <caracicatriz2002@hotmail.com> wrote:
>>Thank you at least I get the year dummies, but again I am facing with a
>>problem;
>>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.
>>
>>d
>>
>>
>>
>> >From: "Scott Merryman" <smerryman@kc.rr.com>
>> >To: <statalist@hsphsun2.harvard.edu>
>> >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).
>> >
>> >Scott
>> >
>> >
>> > > -----Original Message-----
>> > > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-
>> > > statalist@hsphsun2.harvard.edu] On Behalf Of Daghan Yeldan
>> > > Sent: Monday, July 17, 2006 8:15 AM
>> > > To: statalist@hsphsun2.harvard.edu
>> > > 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.
>> >The
>> > > problem I get is when I do this,
>> > >
>> > > tab minder,g(min) it only creates two dummies instead of 3. I have 3
>> >years
>> > > of variables.
>> > > How can I solve this problem?
>> > > cheers,
>> > > d
>> >
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