People in white coveralls sit by a mass grave as bodies are buried in blue bodybags.

Bodies are buried in Rafah in the Gaza Strip. Researchers say deaths have probably gone unrecorded in the region because so much of the population is displaced.Credit: Reuters/Mohammed Salem

Since war broke out in the Gaza Strip almost a year ago, the official number of Palestinians killed exceeds 41,000. But this number has stoked controversy. Some researchers think it is an underestimate, owing to the difficulties of trying to count dead people during conflicts. Other sources say it overestimates the number of casualties. The count comes from the Palestinian Ministry of Health — Gaza, the main institution counting mortality in the region.

It’s important to track fatalities during wars — and to estimate overall mortality — to hold warring parties accountable and to advocate for the protection of civilians, says Zeina Jamaluddine, an epidemiologist at the London School of Hygiene & Tropical Medicine. The number of deaths also informs discussions around when to officially declare that a situation involves famine.

In the heat of conflict, the first way to count fatalities is to tally up the number of dead people. But capturing the number of deaths in the densely populated urban centres of Gaza presents unique challenges, says Emily Tripp, director of Airwars, a non-profit watchdog based in London that counts casualties in times of conflict. “What we’ve seen in Gaza is entire families just being completely wiped out,” says Tripp. That means it can be hard to recover bodies, or there is no one to report them dead, and so deceased people will be missed in counts.

Only when the conflict ends or eases can researchers begin the work of getting more robust estimates of overall mortality through surveys, modelling and statistical tools, they say.

Counting deaths

The Palestinian Ministry of Health — Gaza updates the death count almost daily, and has published five detailed lists of people who have died, including, where possible, full names, national identity numbers, age and sex.

In the first few weeks of the war, the ministry recorded deaths that were reported at hospital morgues1, using a system well established in Gaza. The early lists were detailed enough that researchers, including Jamaluddine and her colleagues1,2, found that the mortality data and daily reporting followed similar trends to the deaths among staff members working at the international agency providing humanitarian assistance in Gaza, the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA). Airwars also found that the ministry’s data were in accord with its own.

But when medical centres came under attack, the ministry’s ability to count fatalities was affected, says Jamaluddine, who noticed the change after the attacks on Al-Shifa Hospital in Gaza City in November. “It became harder and harder as the war broke out.” The World Health Organization reported that as of 17 September, fewer than half of Gaza’s 36 hospitals were still operational, and that those that were were providing only limited services.

Since then, the ministry has had to increasingly rely on deaths reported outside hospital morgues by the Palestinian Civil Defence, the Palestine Red Crescent Society or ministry staff, says Omar Hussein, director of the emergency operations centre at the Ministry of Health in Ramallah. In areas not accessible to these organizations, particularly in northern Gaza, the ministry verifies deaths reported by close relatives, he says.

The ministry’s most recent list of people who have died, published in July, includes complete information on approximately 28,000 people. The ministry reports that there are still some 7,000 people for whom they don’t have complete information, owing to the difficulties in identifying them. Many deaths are still unaccounted for because the people are buried under rubble, says Hussein.

Some deaths could also have been missed because friends and relatives don’t want to report them, or don’t know a person has died. “Nearly everyone in Gaza right now is displaced, so they don’t know where everybody else is, and although most people have cell phones, cell coverage is intermittent,” says Patrick Ball, a statistician and director of research at the non-profit Human Rights Data Analysis Group in San Francisco, California. The medical system could also be too overwhelmed to report them.

But Mark Zlochin, an independent researcher in Pardes Hanna-Karkur, Israel, who has analysed the ministry’s fatalities data, says there is no way to verify the number of deaths for which the ministry has incomplete information. Although he thinks the specific deaths reported through the ministry hospital morgue system — a large portion of the 28,000 deaths recorded in the July list — are probably true casualties, he thinks the ministry’s total reported deaths is probably an overcount. Deaths reported by relatives could include people who have just gone missing, and young children and older individuals who died for reasons not related to the war, he says.

Overall, the ministry’s records are “pretty good” because they include detailed information for most fatalities, and that transparency provides credibility, says Michael Spagat, an economics researcher at Royal Holloway, University of London, in Egham, and chair of the non-profit advocacy group Every Casualty Counts in London.

Besides the ministry, other groups tracking casualties in the region include the UNRWA, which collects information on its staff members who have died; independent organizations such as Airwars and Uppsala University’s Uppsala Conflict Data Program (UCDP) in Sweden, which use ministry data and collect information from local news agencies, non-governmental organizations and local groups that keep track of deaths and report them on social media.

The UCDP recorded more than 36,000 fatalities in Gaza between October and July, and, in upcoming revisions, that sum will probably be closer to the 39,000 reported by the ministry during the same period, says Nanar Hawach, a researcher at the UCDP.

Estimating deaths

Given the uncertainty of counting fatalities during conflict, researchers use other ways to estimate mortality.

One common method uses household surveys, says Debarati Guha-Sapir, an epidemiologist who specializes in civil conflicts at the University of Louvain in Louvain-la-Neuve, Belgium, and is based in Brussels. A sample of the population is asked how many people in their family have died over a specific period of time. This approach has been used to count deaths in conflicts elsewhere, including in Iraq3 and the Central African Republic4.

The situation in Gaza right now is not conducive to a survey, given the level of movement and displacement, say researchers. And it would be irresponsible to send data collectors into an active conflict and put their lives at risk, says Ball.

There are also ethical concerns around intruding on people who lack basic access to food and medication to ask about deaths in their families, says Jamaluddine. Surveys will have to wait for the conflict to end and movement to ease, say researchers.

Another approach is to compare multiple independent lists of fatalities and calculate mortality from the overlap between them. The Human Rights Data Analysis Group used this approach to estimate the number of people killed in Syria between 2011 and 2014. Jamaluddine hopes to use the ministry fatality data in conjunction with those posted on social media by several informal groups to estimate mortality in this way. But Guha-Sapir says this method relies on the population being stable and not moving around, which is often not the case in conflict-affected communities.

In addition to deaths immediately caused by the violence, some civilians die of the spread of infectious diseases, starvation or lack of access to health care. In February, Jamaluddine and her colleagues used modelling to make projections of excess deaths due to the war and found that, in a continued scenario of six months of escalated conflict, 68,650 people could die from traumatic injuries, 2,680 from non-communicable diseases such as cancer and 2,720 from infectious diseases — along with thousands more if an epidemic were to break out. On 30 July, the ministry declared a polio epidemic in Gaza after detecting the virus in sewage samples, and in mid-August it confirmed the first case of polio in 25 years, in a 10-month-old baby.

Survivor stories

The longer the conflict continues, the harder it will be to get reliable estimates, because “reports by survivors get worse as time goes by”, says Jon Pedersen, a demographer at !Mikro in Oslo, who advises international agencies on mortality estimates.

Even after the violence winds down, many factors will influence the reliability of mortality estimates. For example, if the war ends with, essentially, a military occupation by Israel, people who have been hiding deaths from officials might continue to do so out of fear, says Ball. Local trust in the institutional structures set up after the war matters, he says.

But several factors mean that it should be possible to reconstruct the death toll, says Leslie Roberts, an epidemiologist who specializes in measuring mortality and human-rights abuses, and holds an emeritus position at Columbia University in New York City. For example, Gaza’s population is highly educated and the region has strong social networks, making it easier to track where everyone is.