st: ivreg2 with weight: results slightly different to those 3 months ago

["sdm1" <sdm1@york.ac.uk>]

I have been re-running a do file that I last ran in July and I have been
getting slightly different results for most parts of the regression output
when using -ivreg2- with weights (-ivreg2- without weights generates
identical results).  For example, the Kleibergen-Paap rk LM statistic and
Kleibergen-Paap Wald rk F statistic are the same as they were in July but
most of the output changes slightly (including the regression coefficients).

I am now using:

. which ivreg2
c:\ado\plus\i\ivreg2.ado
*! ivreg2 3.0.05  17June2010

I guess that I must have updated the ado file sometime between July and now
because today's log file includes Angrist-Pischke (AP) statistics but the
July log file does not (it first reports Shea's Partial R2).  I do not know
which version of ivreg2 I was using previously.  Sorry!

In both cases I am estimating the same model:

ivreg2 lallcancersdsmr lneed89HPandG (lg2_89expphHPandG=llonepenhx
lpoppucarx) [w=rawpop89], gmm2s robust ffirst endog(lg2_89expphHPandG)

Have changes been made to -ivreg2- (perhaps fairly recently) which would
account for this?

Steve

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