Born in 1961, Les Roberts is an epidemiologist based at the Johns Hopkins School of Public Health in Baltimore. A native New Yorker, Roberts earned his undergraduate degree at St. Lawrence University, a master’s degree in public health from Tulane University, and a Ph.D. in environmental engineering from Johns Hopkins University, where he is currently a lecturer. In addition, he did post-graduate fellowship work at the Center for Disease Control in Atlanta. Prior to his current position at the Bloomberg School, Roberts was a Director of Health Policy at the International Rescue Committee. In 1994 he conducted a study for the World Health Organization to estimate the number of refugees created by the violent Tutsi-Hutu clashes in Rwanda. Six years later he performed a similar study to estimate the number of deaths caused by the war in Congo.

Roberts made headlines in late October 2004, when, a week prior to the U.S. presidential election, his study titled “Mortality Before and After the 2003 Invasion of Iraq: Cluster Sample Survey” was published in the British medical journal Lancet. Roberts was the lead investigator for the study, which was conducted by a group of scientists not only from Johns Hopkins, but also from Al-Mustansirya University in Baghdad and Columbia University in New York.

Roberts was the lead author of the Lancet article, which asserted that somewhere between 69,000 and 155,000 Iraqi civilians had been killed in the Iraq War since its March 2003 beginning. Roberts concluded that the most likely figure was approximately 100,000 deaths nationwide, not including deaths in the city of Fallujah — where the heaviest sustained fighting had taken place. Suggesting that unbridled American aggression was ultimately to blame for the carnage in Iraq, Roberts said it was vital to determine “[h]ow many times Coalition soldiers fire in anger each day and how has that changed over time.”

At the time of the Lancet article’s publication, other estimates of civilian deaths were much lower. For example, British foreign secretary Jack Straw placed the figure at approximately 15,000. Iraq Body Count, a database run by academics and peace activists, said the death toll was between 14,000 and 16,000. The Brookings Institution’s estimates ranged from 10,000 to 27,000.

Roberts’ estimates were based on a door-to-door survey of approximately 30 randomly selected households in each of 33 geographic clusters across Iraq, or a total of 988 homes. Identifying themselves as researchers “from the university,” Roberts’ interviewers — all native Iraqis — asked each respondent to tell them who had been living in his or her home as of January 1, 2002, and whether any of those people had died since then — and if so, when and how. In these households, a total of 142 people were reported as having died in the post-invasion period, 72 of them violently; 51 of those violent deaths had occurred in Fallujah, and just 21 in the other 18 Governorates, or districts, included in the study. From this information, Roberts and his colleagues calculated that Iraqi civilians’ relative risk of dying from any cause was 2.5 times higher after the March 2003 invasion than it had been during the preceding 14-and-a-half months. But if the data from Fallujah was excluded, the figure dropped to 1.5 times the pre-invasion death rate. Stating that “violence was the primary cause of death” after the invasion, Roberts’ report attributed those violent deaths mainly to coalition forces — and identified most of the victims as women and children. “Making conservative assumptions, we think that about 100,000 excess deaths, or more, have happened since the 2003 invasion of Iraq,” said Roberts.

The day after the Lancet article appeared, Fred Kaplan, a defense correspondent for Slate magazine, called Roberts’ estimate of 100,000 deaths “so loose as to be meaningless. … This isn’t an estimate. It’s a dart board.” Despite being a self-proclaimed “persistent and outspoken critic of the Iraq war,” Kaplan said it was crucial for researchers to avoid gearing their “analysis to the conclusions that [they would] like to reach” — implying that Roberts had allowed his personal views to corrupt his findings.

A more detailed critique of Roberts’ methodology was put forth by political consultant Steven E. Moore, who had trained Iraqi researchers for the International Republican Institute from 2003 to 2004, and who had conducted survey research for the Coalition Forces from 2005 to 2006. Moore contended that Roberts had used a woefully inadequate number of cluster points in his research, and that his results were thus not reliable.

Wrote Moore: “What happens when you don’t use enough cluster points in a survey? You get crazy results when compared to a known quantity, or a survey with more cluster points.” Moore cited, as an example, a United Nations Development Program (UNDP) survey conducted in April and May 2004, four months prior to the Roberts study. The UNDP study, which used 66 cluster points, had estimated between 18,000 and 29,000 war-related Iraqi civilian deaths — totals far smaller than those suggested by the Roberts team, which used 33 cluster points.

In an April 2005 interview with the Socialist Worker, Roberts stated, “As far as I’m concerned the exact number of dead is not so important. It is many tens of thousands. Whether it’s 80,000 or 140,000 dead, it’s just not acceptable.”

In July 2005 Roberts authored a paper titled “The Iraq War: Do Civilians Matter?” — published by the MIT Center for International Studies (CIS). In that piece, Roberts attributed Middle Eastern Muslims’ “sudden burst of hatred” for Americans in large measure to the public perception that President Bush had “brusquely dismissed” accusations by Amnesty International (and other organizations) of “a pattern of [American-perpetrated] abuse … in Guantanamo Bay.” He further lamented that “the greatest threat to U.S. national security” was “the image that the United States is a violator of international laws and order and that there is no means other than violence to curb it.”

In the same CIS paper, Roberts wrote: “A report in the New England Journal of Medicine [NEJM] in July 2004, based on interviews with returning U.S. soldiers, suggests an unintentional non-combatant death toll of 133 deaths per day.” To this, John Sloboda, co-founder of Iraq Body Count, wrote an email to Roberts, in which he stated that “nowhere in this cited NEJM paper is there any reference to an estimated per-day rate of violent deaths, whether 133 or any other number, and there is nothing in any of your publications to explain how this 133 per-day rate is derived.”

“You simply cite the undoubtedly prestigious Journal as if it contained the facts you claim for it,” Sloboda told Roberts, “which it does not … We recently contacted the first author of the NEJM paper, Dr. Charles Hoge, who replied as follows: ‘In no way can our data be used … to estimate actual civilian casualty numbers.’ In summary, you [Mr. Roberts] have published a claim, on the basis of the Hoge et al paper, which the lead author of that paper says is unsustainable….”

In mid-October 2006 — once again, shortly before a crucial political election — Roberts and a team of fellow Johns Hopkins researchers released the results of a follow-up to their 2004 study of Iraqi civilian deaths. For this new report, the researchers had gathered data from a sample of 1,849 Iraqi households distributed over 47 cluster points from late May to early July of 2006. According to the survey results, Iraq’s mortality rate in the 15 months prior to the invasion had been 5.5 deaths per 1,000 people per year; in the post-invasion period it was 13.3 deaths per 1,000 people. The difference between these rates was used to calculate “excess deaths” that would not ordinarily have been expected. Based on those figures, the researchers estimated that some 655,000 Iraqi civilians had died from war-related causes between the March 2003 U.S. invasion and the beginning of July 2006.

The aforementioned Steven Moore observed, “The 2004 survey by the Johns Hopkins group was itself methodologically suspect — and the ^[2006] one they just published even more so.” In the October 18, 2006 Wall Street Journal, Moore elaborated: “[T]he key to the validity of cluster sampling is to use enough cluster points. In their 2006 report, ‘Mortality after the 2003 invasion of Iraq: a cross-sectional sample survey,’ the Johns Hopkins team says it used 47 cluster points for their sample of 1,849 interviews. This is astonishing: I wouldn’t survey a junior high school, no less an entire country, using only 47 cluster points.”

By comparison, Moore noted: “For its 2004 survey of Iraq, the United Nations Development Program (UNDP) used 2,200 cluster points of 10 interviews each for a total sample of 21,688. … Appendix A of the Johns Hopkins survey … cites several other studies of mortality in war zones, and uses the citations to validate the group’s use of cluster sampling. One study is by the International Rescue Committee in the Democratic Republic of Congo, which used 750 cluster points. Harvard’s School of Public Health, in a 1992 survey of Iraq, used 271 cluster points. Another study in Kosovo cites the use of 50 cluster points, but this was for a population of just 1.6 million, compared to Iraq’s 27 million.”

“With so few cluster points,” concluded Moore, “it is highly unlikely the Johns Hopkins survey is representative of the population in Iraq.”

The respondents in Roberts’ 2006 survey reported an aggregate total of 629 deaths in their households. Slightly more than three-fourths of the dead were men, with a greater male preponderance after the invasion. The male-to-female ratio of post-invasion violent deaths was 10-to-1, and most of the victims were between 15 and 44 years of age. These figures strongly suggest an effort by U.S. forces to avoid harming women and children. In fact, according to the respondents, just 31 percent of the violent post-invasion deaths of their household members had been caused by coalition forces or air strikes. In the first Roberts study, by contrast, “air strikes from coalition forces accounted for most violent deaths.” This was largely because air strikes were used far more often during the initial invasion period than in subsequent phases of the war. In fact, there were more U.S. air strikes during the first day of the invasion than during the entire year of 2005.

In 2006 the 44-year-old Les Roberts campaigned in the Democratic primary for the U.S. House of Representatives seat of the 24th Congressional District in Chenango County, NY. He withdrew from the running on May 17 and endorsed the remaining Democratic candidate, Michael Arcuri.