I believe the study you're referring to is the one I cited from Johns Hopkins U.
From the Lancelot report:
Lancelot Report
Contributors
L Roberts was the lead investigator in the field and was principally responsible for the data analysis, interpretation, and preparation of this report. R Lafta was involved in study design, hired, trained, and oversaw the interview staff, led one of the two study teams, coordinated all logistical aspects of the study, and had a central role in data interpretation and preparation of this report. R Garfield advised on issues of study design, study execution, participated in the analysis and interpretation of data and preparation of this report, and initially organised the study team. J Khudhairi was involved in the study design, interviewer training, and oversaw one of the two survey teams in the field. G Burnham advised on issues of study design, study execution, participated in the analysis and interpretation of data and preparation of this report, and organised and facilitated the ethics review process at Johns Hopkins University.
Here's a linky that I've posted before about that study. I consider it to be a balanced article about that study:
The Number
Let's just say that there was a lot of criticism as to how the authors did their study. I could post several links but you can find the criticism of the methodology on your own if interested. The article dissusses some of the criticism and the authors of the study reactions to the criticism. The methodology from the Iraqi body count organization is described so it's easy to compare and see why they may have arrived at vastly different numbers. One thing I will note from the article about the study:
"[But] it's absolutely appropriate, on very limited resources, to go into a place like Iraq and make an estimate of excess mortality to use in planning and making decisions. My own sense is I would rather err on the side of generating potentially useful data, with all of the caveats. I think noisy data is better than no data." Zeger notes that the tests of the data's validity, built into the second survey at his recommendation, all checked out. He admits the numbers are hard to grasp, especially the study's estimate that from June 2005 to June 2006, Iraqis were dying at a rate of 1,000 per day. "That's a lot of bodies," he says. "I have a hard time getting my mind around that. But as a scientist, what do you do? That's the number."
This strikes me as kind of George Bush type of comment, hey the number seems ridiculous but I couldn't have erred so it has to be right.