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From |
Erik Aadland <[email protected]> |

To |
"[email protected]" <[email protected]> |

Subject |
RE: st: RE: Merge problem |

Date |
Fri, 4 Oct 2013 12:10:32 +0000 |

Dear Joe. Thank you for your suggestion. The number of periods is not completely fixed in dataset (B). In year == 1, I have periods (1-8) In year == 2, I have periods (9-17) In year == 3, I have periods (18-28) In year == 4, I have periods (29-39) In year == 5, I have periods (40-50) In year == 6, I have periods (51-61) In year == 7, I have periods (62-72) In year == 8, I have periods (73-75) So a total of 75 periods spread over 8 years in dataset (B). Sincerely, Erik. > From: [email protected] > To: [email protected] > Subject: st: RE: Merge problem > Date: Fri, 4 Oct 2013 11:56:06 +0000 > > Erik, > > If there are a fixed, known number of periods per year, you can use -expand- in dataset (A). Suppose (as in your example) there are 4 periods (1,2,3,4): > > . expand 3 > . bys year firm_id: gen period_id=_n > > However, if the number of periods depends on some information in dataset (B), that's a different story. If so, please provide more information on how the number of periods is to be determined. > > Regards, > Joe Canner > Johns Hopkins University School of Medicine > > ________________________________________ > From: [email protected] [[email protected]] on behalf of Erik Aadland [[email protected]] > Sent: Friday, October 04, 2013 4:18 AM > To: [email protected] > Subject: st: Merge problem > > Dear Statalist. > > I have two datasets. One dataset (A) contains the variables "year" and "firm_id". A firm observation ("firm_id") occurs only once in a given "year". > > The other dataset (B) contains the variables "year", "period_id" and "firm_id". There are many periods within a given year, and firm observations ("firm_id") are nested within periods. So a given firm ("firm_id") may occur several times in a given year. The firms in (A) are not the same firms as in (B). The structure of (A) and (B) are as follows. > > (A): > year firm_id > 2003 1 > 2003 2 > 2003 3 > 2003 4 > 2004 1 > 2004 2 > 2004 5 > 2004 6 > > (B): > year period_id firm_id > 2003 1 11 > 2003 1 12 > 2003 2 13 > 2003 2 14 > 2003 2 11 > 2004 3 11 > 2004 3 12 > 2004 3 15 > 2004 4 16 > 2004 4 17 > > I want to merge the firms in (A) into (B) such that the firms in (A) in a given year occur in all periods for the corresponding year in (B). The problem is that I don't have "period_id" for my firm observations in (A). > > Is there a smart way to handle this problem? I use Stata 12. > > Any input on this would be much appreciated. > > Sincerely, > Erik > * > * 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/

**Follow-Ups**:**RE: st: RE: Merge problem***From:*Erik Aadland <[email protected]>

**References**:**st: Merge problem***From:*Erik Aadland <[email protected]>

**st: RE: Merge problem***From:*Joe Canner <[email protected]>

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