Re: st: dates in stata

["E. Paul Wileyto" <epw@mail.med.upenn.edu>]

Your date is entered as a string, not a real date format.  Real dates 
are integer values, representing (currently) the number of days elapsed 
since January 1st 1960.
Try this:
> . edit
> (1 var, 13 obs pasted into editor)
>
> . list
>
>      +------------------+
>      |             var1 |
>      |------------------|
>   1. |    01 April 2005 |
>   2. |    01 April 2008 |
>   3. |   01 August 2000 |
>   4. |   01 August 2001 |
>   5. |   01 August 2002 |
>      |------------------|
>   6. |   01 August 2003 |
>   7. |   01 August 2005 |
>   8. |   01 August 2006 |
>   9. |   01 August 2007 |
>  10. |   01 August 2008 |
>      |------------------|
>  11. | 01 December 2000 |
>  12. | 01 December 2003 |
>  13. | 01 December 2004 |
>      +------------------+
>
> . gen dateval=date( var1, "DMY")
>
> . list
>
>      +----------------------------+
>      |             var1   dateval |
>      |----------------------------|
>   1. |    01 April 2005     16527 |
>   2. |    01 April 2008     17623 |
>   3. |   01 August 2000     14823 |
>   4. |   01 August 2001     15188 |
>   5. |   01 August 2002     15553 |
>      |----------------------------|
>   6. |   01 August 2003     15918 |
>   7. |   01 August 2005     16649 |
>   8. |   01 August 2006     17014 |
>   9. |   01 August 2007     17379 |
>  10. |   01 August 2008     17745 |
>      |----------------------------|
>  11. | 01 December 2000     14945 |
>  12. | 01 December 2003     16040 |
>  13. | 01 December 2004     16406 |
>      +----------------------------+
>
> . format  dateval %d
>
> . list
>
>      +------------------------------+
>      |             var1     dateval |
>      |------------------------------|
>   1. |    01 April 2005   01apr2005 |
>   2. |    01 April 2008   01apr2008 |
>   3. |   01 August 2000   01aug2000 |
>   4. |   01 August 2001   01aug2001 |
>   5. |   01 August 2002   01aug2002 |
>      |------------------------------|
>   6. |   01 August 2003   01aug2003 |
>   7. |   01 August 2005   01aug2005 |
>   8. |   01 August 2006   01aug2006 |
>   9. |   01 August 2007   01aug2007 |
>  10. |   01 August 2008   01aug2008 |
>      |------------------------------|
>  11. | 01 December 2000   01dec2000 |
>  12. | 01 December 2003   01dec2003 |
>  13. | 01 December 2004   01dec2004 |
>      +------------------------------+
>
> . sort dateval
>
> . list
>
>      +------------------------------+
>      |             var1     dateval |
>      |------------------------------|
>   1. |   01 August 2000   01aug2000 |
>   2. | 01 December 2000   01dec2000 |
>   3. |   01 August 2001   01aug2001 |
>   4. |   01 August 2002   01aug2002 |
>   5. |   01 August 2003   01aug2003 |
>      |------------------------------|
>   6. | 01 December 2003   01dec2003 |
>   7. | 01 December 2004   01dec2004 |
>   8. |    01 April 2005   01apr2005 |
>   9. |   01 August 2005   01aug2005 |
>  10. |   01 August 2006   01aug2006 |
>      |------------------------------|
>  11. |   01 August 2007   01aug2007 |
>  12. |    01 April 2008   01apr2008 |
>  13. |   01 August 2008   01aug2008 |
>      +------------------------------+
>
> .







lschoele@rumms.uni-mannheim.de wrote:
> Hello Statalist,
>
> I am using Stata for event study. I entered all my variables and 
> observations.
> Regarding my variable "date" I have a problem. When I use "sort date", 
> stata  sorts the date shown above:date
> 01 April 2002
> 01 April 2003
> 01 April 2004
> 01 April 2005
> 01 April 2008
> 01 August 2000
> 01 August 2001
> 01 August 2002
> 01 August 2003
> 01 August 2005
> 01 August 2006
> 01 August 2007
> 01 August 2008
> 01 December 2000
> 01 December 2003
> 01 December 2004
> 01 December 2005
> 01 December 2006
> 01 February 2000
> 01 February 2001
> 01 February 2002
> 01 February 2005
> 01 February 2006
> 01 February 2007
> 01 February 2008
> 01 July 2002
> 01 July 2003
> 01 July 2004
> 01 July 2005
> 01 July 2008
> 01 June 2000
> 01 June 2001
> 01 June 2004
> 01 June 2005
> 01 June 2006
> 01 June 2007
> 01 March 2000
> 01 March 2001
> 01 March 2002
> 01 March 2004
> 01 March 2005
> 01 March 2006
> 01 March 2007
> 01 May 2000
> 01 May 2001
>
> I can tell that stata sorts by the first letter of the month. Do I 
> have to use a special format for the date? I also tried the format 
> 01.04.2002, but that gives me the same sortation shown above.
>
> Can anyone help me?
>
> Best regards
> Lisa
>
>
>
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--
E. Paul Wileyto, Ph.D.
Assistant Professor of Biostatistics
Tobacco Use Research Center
School of Medicine, U. of Pennsylvania
3535 Market Street, Suite 4100
Philadelphia, PA  19104-3309

215-746-7147
Fax: 215-746-7140
epw@mail.med.upenn.edu



*
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