The authorities commissioned researchers at George Washington University’s Milken Institute of Public Health to do this work, which has not yet been completed. However, the researchers came back with an initial report in August, which compared the total number of deaths that occurred in the months after the hurricanes with the number that would normally have been expected.

This provided the scientific foundation upon which the territorial government immediately announced that it was revising its death toll estimate upward, to match the numbers in the new report.

Is it legitimate to count both direct and indirect deaths?

The federal government says yes. In relation to hurricane deaths, the term “direct” means those that occurred from drowning or other effects of the storm itself. “Indirect” deaths include those in which related factors, such as difficulty reaching a hospital for care, or trouble refilling medical prescriptions, played a role.

George Washington researchers said they found that doctors in Puerto Rico at the time of the storm were not aware of new guidelines from the federal Centers for Disease Control and Prevention, released the month after the hurricane, which recommend that doctors also consider a natural disaster’s indirect impacts in assessing how to tally deaths.

What was The New York Times’s estimate?

In December, The New York Times analyzed vital statistics from the Puerto Rican government. They showed that in the 42 days after Hurricane Maria made landfall on Sept. 20, 2017, 1,052 more people than usual died in Puerto Rico.

That figure was particularly striking because thousands of people had left the island, including many with chronic medical conditions. Based on the likelihood that the population there was smaller in the fall of 2017, we would have expected the number of deaths per day to decrease, not increase.

To obtain our figure of 1,052, we compared the number of deaths for each day in 2017 with the average of the number of deaths for the same days in 2015 and 2016. The figures came from the Puerto Rican government, which provided us with tables showing the number of deaths per day and deaths broken down by cause. The 2017 numbers were preliminary, so we limited our analysis to September and October.