A controversial new Canadian study, suggesting death rates usually decline when wars erupt, is sparking furious debate among scholars and activists around the world.

The study, by researchers at Simon Fraser University in Vancouver, found provocative new evidence for the counterintuitive notion that mortality rates in wartorn countries are actually declining in most cases – largely because of improving public health, smaller wars, and an influx of humanitarian aid for countries at war.

The study questions the long-accepted estimate that 5.4 million people have died in Congo's civil war, concluding that the number is much smaller.

Critics have lashed out at the study, warning it leaves the world “more ignorant” about the true cost of war. The estimate of 5.4 million deaths has helped to mobilize humanitarian aid for the impoverished people of Congo, and activists worry the new study could be an excuse to slash this aid.

The study's director, Andrew Mack of the Human Security Report Project at Simon Fraser, is sticking to his guns. In e-mails to The Globe and Mail, he strongly defended his research and insisted it will not undermine the international campaign to help the Democratic Republic of Congo, which has been ravaged by war for the past 12 years.

He also argues that international relief agencies – such as the International Rescue Committee, which produced the estimate of 5.4 million dead in the Congo – are facing a potential conflict of interest because they depend on donations that, in turn, are stimulated by their studies of death tolls. Those studies should be done by independent experts, not by relief agencies that depend on donations, he says.

The arguments may seem academic, but the implications are huge. If death counts are exaggerated, it can create suspicion and distrust between governments and foreign donors, hampering aid and making it harder for relief agencies to operate. Sudan, for example, has restricted the work of relief agencies in Darfur, partly because of its anger that the U.S.-based Save Darfur Coalition had estimated that 400,000 people were killed in Darfur – a number that many experts have questioned.

The study by Prof. Mack and his researchers, financed by several governments and institutes, looked at 18 African countries affected by wars since 1970. It found a paradoxical result: the mortality rate for children younger than 5 actually declined during periods of warfare in 14 of those 18 countries. It also cites evidence from a World Bank study suggesting that adult mortality similarly declines in periods of wartime, and not just in Africa.

“No one of course is suggesting that war causes mortality rates to decline,” the report says. “The reality is simply that today's armed conflicts rarely generate enough fatalities to reverse the long-term downward trend in peacetime mortality that has become the norm for most of the developing world.”

The decline in wartime mortality is largely due to public health measures such as immunization, along with a dramatic rise in humanitarian aid, the study says. The level of aid for the average refugee or displaced person has tripled over the past 20 years, and this has caused fatality rates for malnourished children to plummet. Even in Congo, immunizations have increased dramatically since the beginning of the war.

“The evidence is clear that international action can play – and indeed has played – a critically important role in reducing the human costs of war,” the study says.

In the Congo war, disease and malnutrition accounted for more than 90 per cent of the often-cited estimate of 5.4 million deaths. But the study argues that this estimate is badly flawed by methodological errors, including an assumption that Congo had an average mortality rate before the war, when in fact it had one of the worst mortality rates in Africa.

The International Rescue Committee has rejected the Simon Fraser study, saying that its estimate of war-related deaths was extensively peer-reviewed, published in three medical journals, and accepted by independent experts.

Les Roberts, a Columbia University scholar who participated in some of the IRC's surveys in Congo, said the Simon Fraser study was based on “poor scholarship and limited evidence.” If the study had focused on the biggest wars in Africa, rather than including a large number of smaller conflicts, its conclusions would probably have been reversed, he said in a written analysis of the study.

“The Canadian government should be mortified by this report,” Prof. Roberts said. He said he was “disheartened” to see so much money spent on a report that will “make the academic community more fractious.”

Prof. Mack, meanwhile, says he and his research team are still standing by their conclusions. He says they will soon be releasing “compelling new evidence” that the Congo death counts were “grossly exaggerated.”