Efrain Perez died inside an ambulance after being turned away from the island’s largest public hospital days after Hurricane Maria, when the facility had no electricity or water.Carlos Giust / AP

The grisly business of counting the dead after a natural disaster would seem to be a straightforward one. There is a certain number of people alive before the event, and there is a certain number after. Subtraction should yield a figure similar to the number of death certificates issued, and the number of loved ones families claim have been lost. That total, a composite of incalculable amounts of personal and familial grief, is how people make rough estimates of a disaster’s magnitude and scope.

As the past year of pain and uncertainty in Puerto Rico can attest, in reality, this accounting isn’t so easy. Two major studies of mortality—and several additional estimates—have contained wildly different numbers, and their differences have only inflamed a debate over accountability and lapses in communication. They’ve also underscored the collapse of official systems and the disastrous response by multiple levels of government. The very act of counting the dead has transformed from a tragic, but standard, task of government to a months-long bureaucratic nightmare that has indicted deficiencies in both Puerto Rico and Washington.

Now the definitive estimate that researchers, policy makers, and aggrieved loved ones have been waiting for has finally arrived. On Tuesday, researchers from the George Washington University Milken Institute School of Public Health released a series of studies on Hurricane Maria’s impact in Puerto Rico. The mortality study, completed at the official request of Puerto Rican Governor Ricardo Rosselló and administered in conjunction with the University of Puerto Rico, analyzed official Puerto Rican vital statistics to find that the hurricane resulted in 2,975 excess deaths from its landfall in September 2017 to February 2018. Two complementary studies in the same report illustrate major deficiencies in the island’s disaster communications, as well as a mass confusion among health professionals over how to complete death certificates after the storm.

The big number is the one that will elicit the most media response from the study: Almost 3,000 people were killed by Hurricane Maria in Puerto Rico. The total, which was estimated using a full government-supplied data set and a complex model, will likely be cited as the most reliable account of the death toll. It is presented in a similar way to previous estimates. As in other studies, the GW researchers essentially modeled what the death rate in Puerto Rico would’ve looked like if Maria hadn’t hit, and then used that number from September to the following February as a baseline. The estimate of real-life deaths above that baseline are the “excess deaths” estimated throughout that period. The 95 percent confidence interval, or the range in which researchers can reasonably expect the precise total to fall, is from 2,658 to 3,290 dead. Any of these numbers—from the low to the high end—would make Hurricane Maria one of the most massive disasters of any kind in modern American history.

But the report is as interested in the genesis of that number as in the death toll itself. As opposed to an influential investigation from Harvard researchers earlier in the summer, which estimated more than 4,000 deaths but had a wide confidence interval, this study used official death certificates from Puerto Rico’s health department. And as opposed to a study of administrative data posted earlier this month, which reported 1,139 deaths from September to December, this effort also modeled the staggering amount of migration triggered by Maria—almost a tenth of the population of Puerto Rico left in the aftermath of the storm—and registered continued spikes in deaths through February.

The level of detail in this analysis allowed researchers to shed light on the disparate impacts of the storm’s destruction within Puerto Rican populations. Based on the long period of excess deaths in the disaster-response phase, previous models gestured at the possibility that much of the burden of mortality didn’t come directly from the storm’s damage, but as infrastructure and other vital systems collapsed. The GW study confirms that prediction with much more clarity. “Certain groups—those in lower income areas and the elderly—faced the highest risk,” said Carlos Santos-Burgoa, a GW professor and the principal investigator, in a statement.

In particular, the study found that death rates in the lowest-income areas peaked at about 60 percent higher than baseline in the aftermath of the storm. That’s compared with a 20 percent overall increase in deaths across the island. Those results seem to comport with the infrastructure and health-care deficiencies many observers noted in the aftermath of the storm, which disproportionately affected lower-income areas. Places like the small island of Vieques, which lost its water and electricity—and for a time relied on ad hoc (and illegal) deliveries of goods by volunteers in an airplane—suffered the highest average excess mortality.

The researchers provide a concrete explanation for why the long-standing official death toll was so inadequate. For months, the territory’s government claimed that the number was only 64 deaths. The GW team discovered that physicians and other health professionals tasked with filling out death certificates were not comfortable with attributing deaths to the hurricane. “The official government estimate of 64 deaths from the hurricane is low primarily because the conventions used for causal attribution only allowed for classification of deaths attributable directly to the storm, e.g., those caused by structural collapse, flying debris, floods and drownings,” the report notes. “During our broader study, we found that many physicians were not oriented in the appropriate certification protocol.This translated into an inadequate indicator for monitoring mortality in the hurricane’s aftermath.”

There are a number of other important findings in this comprehensive report, including the fact that, while the storm did create a major lag in filing death certificates, physicians did eventually file records thoroughly and consistently. This finding eliminates one major potential problem: Despite the overall systems collapse, Puerto Rico’s health-care infrastructure was resilient to some point.

In more ignominious news for the island, a separate study within the same GW report finds that Puerto Rico’s disaster-response and disaster-communications preparedness were woefully inadequate. Instead of including scenarios involving multiple systems failures, as specified in Department of Homeland Security preparedness guidelines for the kind of Category 3 hurricanes the Caribbean regularly faces, the island territory was only prepared for Category 1 storms. Large numbers of communications professionals were not trained for disasters or crises. And the perception of risk among the population was affected by the government’s top-to-bottom lack of readiness.

In all, this report should be one of the final words in assessing Maria’s death toll. But in terms of culpability, responsibility, and preparedness for the next storm, it’s still only the beginning. What the GW report confirms is that, in terms of the number of Americans dead, Maria was a disaster on the scale of the September 11 terrorist attacks. Those attacks triggered changes to many American systems, from how people board planes to how they can open bank accounts. As Representative Nydia Velázquez—the sponsor of a proposed “9/11-style” commission to investigate federal and local failures during Maria—has emphasized, the scale of those attacks changed the entire character of the country. Will news of the most devastating natural disaster in decades change anything in Puerto Rico?

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