Here is the Fred Kaplan article* from 2004 about the first study that lays out a lot of the problems in the first study and are many of the factors I'm wondering if they were corrected for this time around.
The one that I wonder most about is the argument that the 2004 study used a pre-war mortality rate for Iraq that was 33% too low which would massively inflate the number of "extraneous" deaths.
And the 95% confidence interval for the 2004 study
was 92%. That is, they said the number was 98,000 but that they were 95% confident it was between 8,000 and 194,000. A range so as to make the result almost meaningless.
I'm reading the full article now to see if these were addressed (though I early on I see that they are still using what is likely a low pre-war mortality rate).
*And just for anybody not familiar with the source Kaplan is solidly anti-Bush and pretty negative on the war.