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| From | "Kyrizi, Andri" <ak196@leicester.ac.uk> |
| To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
| Subject | RE: st: Instrument Validity tests for Heckman 1979 |
| Date | Wed, 12 Mar 2014 16:58:05 +0000 |
Dear Professor Schaffer, Thank you for the information. I tried it but I couldn't get the first heckman regression. I kept getting Iteration 61: log likelihood = -2057.582 with no estimations. Would it be because I use BHPS and has many observations? All the best, Andri ________________________________________ From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] on behalf of Schaffer, Mark E [M.E.Schaffer@hw.ac.uk] Sent: 12 March 2014 16:23 To: statalist@hsphsun2.harvard.edu Subject: RE: st: Instrument Validity tests for Heckman 1979 Andri, > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu [mailto:owner- > statalist@hsphsun2.harvard.edu] On Behalf Of Kyrizi, Andri > Sent: 12 March 2014 16:05 > To: statalist@hsphsun2.harvard.edu > Subject: RE: st: Instrument Validity tests for Heckman 1979 > > Professor Schaffer, > > I checked it but I wasn't sure if the selection bias is controlled for if you do > not specify the group.