In light of this bloodshed, coming just months after the shocking murder of 17 aid workers from the NGO Action Against Hunger in Sri Lanka, aid workers can be forgiven for feeling more and more that they are in the crosshairs. Indeed, theirs is a perilous profession.

Between 1997 and 2005, nearly as many aid workers were killed in the line of duty as were international peacekeeping troops.

International aid work has the fifth highest job-related death rate among U.S. civilian occupations, and is the only one for which the cause of death is predominantly intentional violence.

Between 1997 and 2005, nearly as many aid workers were killed in the line of duty as were international peacekeeping troops.

With each attack seemingly more sensational and horrifying than the last, there is a natural tendency to speak in terms of crisis and sea-change.

For the past several years, and particularly since the experiences in Afghanistan and Iraq, the perception had grown that aid workers were becoming targets of choice and were at greater risk than ever before.

We at the Center on International Cooperation of New York University and the Humanitarian Policy Group of the Overseas Development Institute tested this perception by constructing a global dataset of major incidents of violence against aid workers between 1997 and 2005. We came up with the following findings:

Attacks on aid workers have risen sharply in absolute terms, but the relative increase is far less dramatic.

Since 1997, the absolute numbers

International aid work has the fifth highest job-related death rate among U.S. civilian occupations, and is the only one for which the cause of death is predominantly intentional violence.

of reported major acts of violence committed against aid workers around the world have increased sharply, with the rise growing steeper in the second half of the decade.

On average, annual incidents nearly doubled from the period 1997-2001 to 2002-2005. Between 1997 and 2005, 408 separate acts of major violence were perpetrated against aid workers over the nine-year period, involving 947 victims and including 434 fatalities. By the last days of 2006, total victims had topped 1,100, and the death toll had reached 520.

However, the situation — while unquestionably bad — is not quite as grim as these numbers suggest.

When the number of victims is compared to the expanding population of aid workers in the field, the trend of violence against aid workers is seen to have risen by a considerably smaller amount.

The study calculated the total aid worker population to have grown by 77%

Attacks on aid workers have risen sharply in absolute terms, but the relative increase is far less dramatic.

over the time period, from an estimated 136,000 aid workers in 1997 to an estimated 242,000 in 2005.

Using these population figures, the study found that the annual number of victims per 10,000 aid workers in the field averaged five in the first half of the period and six in the second.

Moreover, in the six most dangerous areas — Afghanistan, the Democratic Republic of Congo, Iraq, North Caucasus, Somalia and Sudan — the overall incident rate per field staff actually decreased over the time period.

In other words, even as incidents in these contexts were rising, they were outstripped by the number of field staff being deployed.

When international aid workers die in the field, it is more likely to be from intentional violence than from any other cause, including illness and vehicle accidents.

Accidental landmine explosions and situations where aid workers are caught in the crossfire between warring parties represent a very small portion of total major incidents. In the vast majority of cases, the aid workers were deliberately targeted.

Many aid workers have complained that the presence and certain actions of foreign forces tends to blur the lines between aid work and the political-military agenda.

Furthermore, although they are certainly attractive targets for simple robbery, in most of the incidents where major violence was used, the perpetrators had political motivations as well.

In the nine years between 1997 and 2005, politically motivated incidents were seen to increase at a rate faster than the “purely criminal” attacks.

Some have taken this observation to prove that aid worker violence is merely a symptom of the general conflict environment, and that aid workers are targeted by association with political or military actors.

Many aid workers have complained that the presence and certain actions of foreign forces — mainly the United States, the UN and NATO — tends to blur the lines between aid work and the political-military agenda and can result directly in violence against aid workers for their perceived association with these actors.

Analysis of the incident data does not bear this out, however. Instead, it shows a more complex picture regarding the targeting of aid workers.

The goal of the perpetrators is often to divert, disrupt or punish the delivery of aid for political or strategic reasons.

To begin with, the most dangerous operational environments for aid workers were found not to be those with the highest level of overall violence, as measured by conflict-related deaths per year.

In fact, the analysis revealed that incidents against international staff show a slight increase in areas where there is no active conflict.

These same incidents also increase where a UN-sanctioned peacekeeping force is present, most likely indicating a sense of increased security leading to freer movement and possibly less vigilant security measures taken by internationals.

Moreover, there was found to be no correlation between aid worker violence and either the presence of great power — e.g., U.S. military forces — or the presence of global terrorist cells.

Careful study of the incidents suggests that when aid workers are targeted for political reasons, it is at least as likely to be for motives relating to the aid work itself as a blow against perceived agents of the enemy.

Accidental landmine explosions and situations where aid workers are caught in the crossfire between warring parties represent a very small portion of total major incidents.

In other words, the goal of the perpetrators is often to divert, disrupt or punish the delivery of aid for political or strategic reasons.

For non-state militant organizations, whether rebels, transnational terror cells or criminal syndicates, attacking aid workers can simultaneously serve a number of key interests.

For example, such attacks can attract visibility in the media and raise their profile as players to be reckoned with on the international stage.

They are also useful for terrorizing local populations who see the flight of aid workers as a loss not only of critical supplies, but also of what may be seen as the last vestige of civilized social order.

Not least, it can generate income through ransoms or the seizing of considerable humanitarian relief assets — including vehicles, communications equipment, food and relief supplies and the considerable sums of cash that aid operations require in settings with no functional banking system.