Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: st: dividend programming question
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: dividend programming question
Date
Sat, 23 Mar 2013 19:57:05 +0000
As said, do look at the -help- for -fillin-. It will help with your gaps.
Also, I am signing off for today.
Nick
On Sat, Mar 23, 2013 at 7:51 PM, Khieu, Hinh <[email protected]> wrote:
> 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.
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/faqs/resources/statalist-faq/
> * http://www.ats.ucla.edu/stat/stata/
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/faqs/resources/statalist-faq/
> * http://www.ats.ucla.edu/stat/stata/
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/faqs/resources/statalist-faq/
* http://www.ats.ucla.edu/stat/stata/