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From | Hong Nguyen <nguyen@scranton.edu> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: RE: A Previous Question on Selecting Sample from Panel Data |
Date | Fri, 18 Jun 2010 11:47:11 -0400 |
Hi Nick, Thank you!Your new commands work in that I could now use either 2000 or 2001 (or both years) for selecting a sample and spread the observations to the other years.
Hong Nick Cox wrote:
This is not very clear. What do you mean by "seems to work, but somehownot quite"?gen byte OK = 1 if interestonly == 1 & (yearid == 2000 | yearid == 2001) bysort gvkey (OK) : replace OK = OK[1]is one way to do it.gen byte OK == interestonly == 1 & (yearid == 2000 | yearid == 2001)bysort gvkey (OK) : replace OK = OK[_N] is another way to do it. Nick n.j.cox@durham.ac.ukHong Nguyen The procedure (that is,bysort firm (derivuse) : replace derivuse = derivuse[1] ==1) seems to work, but somehow not quite.I have 19 years (YEARID=1987, 1988, ..., 2005 already in the data set) of financial data for 423 firms set up as panel data, each firm with a unique GVKEY. For 2000 and 2001 only, I have a variable called INTERESTONLY, which is either 1 or 0 for these 423 firms. What I want todo is to pick observations for a sample of firms where INTERESTONLY=1 (in 2000 only or in 2001 only, or in either), and spread them to all other years.I hope this makes things clearer as to what I have and what I'd like to be able to do.* * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/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/statalist/faq * http://www.ats.ucla.edu/stat/stata/