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RE: st: dividend programming question
From
"Khieu, Hinh" <[email protected]>
To
"'[email protected]'" <[email protected]>
Subject
RE: st: dividend programming question
Date
Sat, 23 Mar 2013 19:51:40 +0000
Nick,
Thanks so much for your prompt help.
Here's what I meant for question #2: Let's say I have firm A and firm B below. I want to create a binary variable called Omission. Firm B has dots, but Firm A do not have any records for div paid from 1997-2001.
FirmA Div paid Omission
1995 .10 0
1996 .10 1
2002 .15 0
2003 .15 0
2004 .15 0
2005 .10 0
2006 .10 0
2007 .10 0
2008 .10 0
2009 .12 0
2010 .12 0
2011 .12 0
2012 .15 0
FirmB Div paid Omission
1995 .10 0
1996 .10 0
1997 . 1
1998 . 1
1999 . 1
2000 . 1
2001 . 1
2002 .15 0
2003 .15 0
2004 .15 0
2005 .10 0
2006 .10 0
2007 .10 0
2008 .10 0
2009 .12 0
2010 .12 0
2011 .12 0
2012 .15 0
Again, I really appreciate any help here.
Regards,
Hinh
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Nick Cox
Sent: Saturday, March 23, 2013 2:29 PM
To: [email protected]
Subject: Re: st: dividend programming question
#1. Given
firmid year dividend
the first year when -dividend- > 0 is
egen yearfirstpaid = min(year / (dividend > 0)), by(firmid)
and so an indicator for first year is
gen wasfirst = year == yearfirstpaid
#2. Not clear to me. You seem to be saying both that you do and do not have observations for certain years. Please review Stata terminology:
an observation is a record, case, or row (and _not_ a value)
a value is the value of a variable
missing values are present in the data, but missing
If observations are not present in the data, they are (in my view) better called "omitted" or "not present".
See -help fillin- as a first step.
Nick
On Sat, Mar 23, 2013 at 6:45 PM, Khieu, Hinh <[email protected]> wrote:
> I have an unbalanced time series data: firm ID, year, and annual
> dividend amount. I want to create 2 binary variables
>
>
>
> 1/ indicating when firm A pays dividends for the first time. Firms
> may enter the dataset and pay div for the first time right at the
> first data entry (example: firm A first appears in data 1990 and pays
> div in 1990, and the variable should be 1 for 1990 and zero for other
> years. Firms may enter the data set and do not pay any div until 5
> years later (example: first appear in data 1990 and pay div in 1995,
> and dummy should be 1 for 1995 and zero for other years.) What makes
> it complicated is that firms may skip paying div for some years and
> come back starting to pay div again. The same binary variable should
> be 1 if the firm does not pay div for 5 years and starts repaying div
> in year 6 (example: first appear in data 1990 and pay div in 1995, and
> dummy should be 1 for 1995 and firm does not pay any div in years 1996
> through 2001 and starts paying div in 2002, dummy should be zero for
> 1996-2001 and 1 for 2002 and zero for other years.)
>
>
>
> 2/ the second dummy captures the omission of dividends above. If firm A pays div in 1995-1996, stops paying from 1997-2001, and pays again 2002 to 2013, dummy should be zero for 1995-1996, one for 1997-2001, and zero again 2002-2013. The problem is that sometimes observations for 1997-2001 are just dots, sometimes the observations are like this (year 1997-2001 are not there):
>
> FirmA Div paid
>
> 1995 .10
>
> 1996 .10
>
> 2002 .15
>
> 2003 .15
>
> 2004 .15
>
> 2005 .10
>
> 2006 .10
>
> 2007 .10
>
> 2008 .10
>
> 2009 .12
>
> 2010 .12
>
> 2011 .12
>
> 2012 .15
>
>
>
> In this case, I want the omission dummy to be 1 in year 1996.
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