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###Excess mortality

Excess mortality

An excess mortality statistic compares an expected number of deaths (including a measure of the uncertainty in that expected number) with an observed number of deaths. This involves examining a set of data to predict the number of deaths in a counterfactual scenario -- one where an event didn't occur.

The excess mortality, then, is the number of deaths above and beyond what is predicted. It is specifically a measure of how much worse things were after Hurricane Maria than the previous 7 years would predict.

An excess mortality statistic compares an expected number of deaths (including a measure of the uncertainty in that expected number, based on the variability) with an observed number of deaths. This involves examining a set of data to predict the number of deaths in a counterfactual scenario -- one where an event didn't occur.

The excess mortality, then, is the number of deaths above and beyond what is predicted. It is specifically a measure of how much worse things were after Hurricane Maria than the previous 7 years would predict. When politicians and pundits state that the excess mortality includes deaths from all causes as a way to call the measure into question, or say that Puerto Rico is in the middle of a financial crisis, or has infrastructure problems, so those people would have died anyway, they are entirely missing the point of an excess mortality analysis. In a Caribbean island that has had its share of hurricanes and tropical storms in the period used for the prediction model, the model expects storms during hurricane season and deaths due to those storms. You subtract actual deaths (all causes) from predicted deaths (all causes). Cancer deaths are in both numbers. Storm deaths are in both numbers. The statistic is the difference.

It seems the answer to this question has turned toward an argument about whether it is a new standard to include indirect deaths when discussing deaths caused by a hurricane. As per some comments, this change was made for Hurricane Maria in order to make Trump look bad, and death reports are a partisan issue where pro-Trump people have one fact and anti-Trump people have another fact. This is not a new standard. The inclusion of indirect deaths in fatality reports from hurricanes occurred for previous hurricanes. It is not a partisan decision to do so.

Perhaps this shouldn't be included as an answer to this question, but the details seem to be easy to lose in comments. I'm open to suggestions for how to appropriately contribute this information to an answer re: the claim "Is President Trump correct that the official death toll figure is grossly exaggerated?" Perhaps it's better as an answer to a different question: was the reporting standard changed for Hurricane Maria (in order to make Trump look bad)?

Hurricane Katrina's death toll:

According to the National Hurricane Center, 1,836 fatalities can be attributed to the storm... many of the deaths are indirect

Hurricane Harvey's death toll

Harvey caused at least 107 confirmed deaths: 1 in Guyana, and 106 in the United States.

From the side bar:

68 direct, 39 indirect

Hurricane Sandy's death toll

At least 233 people were killed across the United States, the Caribbean, and Canada, as a result of the storm

From the table:

106 direct 87 indirect

###Excess mortality

It might be useful here to explain the excess mortality statistic the official death toll is based off. This is the statistic (2,975 (95% CI: 2,658-3,290)) the claim refers to as a gross exaggeration.

An excess mortality statistic compares an expected number of deaths (including a measure of the uncertainty in that expected number) with an observed number of deaths. This involves examining a set of data to predict the number of deaths in a counterfactual scenario -- one where an event didn't occur.

In the GW analysis, the prediction model is based on data on the mortality rate and its variability over a period of 7 years. In addition to crude mortality rates, it analyzes rates for subgroups (age, sex, and SES). It is important to recognize that the prediction model includes all of the deaths over those 7 years, including 7 seasons of tropical storms that affected Puerto Rico. During this period, people died as a result of the residual effect of Bonnie and Earl, as well as all the entire impact of Otto, Emily, Irene, Bertha, Cristobal, and other unnamed storms. In addition to including previous storm related deaths, the prediction model includes the mortality impact of Puerto Rico's many public health challenges, and a particularly bad year for the Caribbean in general.

The excess mortality, then, is the number of deaths above and beyond what is predicted. It is specifically a measure of how much worse things were after Hurricane Maria than the previous 7 years would predict.

It seems the answer to this question has turned toward an argument about whether it is a new standard to include indirect deaths when discussing deaths caused by a hurricane. Some comments have said that reports are including indirect deaths for Hurricane Maria in order to make Trump look bad, suggesting death reports are a partisan issue where pro-Trump people have one fact and anti-Trump people have another fact. These comments are wrong. This is not a new standard. The inclusion of indirect deaths in fatality reports from hurricanes occurred for previous hurricanes. It is not a partisan decision to include them. As you can see below, death reports for prior major hurricanes include indirect deaths.

Perhaps this shouldn't be included as an answer to this question, but the details seem to be easy to lose in comments. I'm open to suggestions for how to appropriately contribute this information to an answer re: the claim "Is President Trump correct that the official death toll figure is grossly exaggerated?" Perhaps it's better as an answer to a different question: was the reporting standard changed for Hurricane Maria (in order to make Trump look bad)?

Hurricane Katrina's death toll:

According to the National Hurricane Center, 1,836 fatalities can be attributed to the storm... many of the deaths are indirect

Hurricane Harvey's death toll

Harvey caused at least 107 confirmed deaths: 1 in Guyana, and 106 in the United States.

From the side bar:

68 direct, 39 indirect

Hurricane Sandy's death toll

At least 233 people were killed across the United States, the Caribbean, and Canada, as a result of the storm

From the table:

106 direct 87 indirect

###Excess mortality

It might be useful here to explain the excess mortality statistic the official death toll is based off. This is the statistic (2,975 (95% CI: 2,658-3,290)) the claim refers to as a gross exaggeration.

An excess mortality statistic compares an expected number of deaths (including a measure of the uncertainty in that expected number) with an observed number of deaths. This involves examining a set of data to predict the number of deaths in a counterfactual scenario -- one where an event didn't occur.

In the GW analysis, the prediction model is based on data on the mortality rate and its variability over a period of 7 years. In addition to crude mortality rates, it analyzes rates for subgroups (age, sex, and SES). It is important to recognize that the prediction model includes all of the deaths over those 7 years, including 7 seasons of tropical storms that affected Puerto Rico. During this period, people died as a result of the residual effect of Bonnie and Earl, as well as all the entire impact of Otto, Emily, Irene, Bertha, Cristobal, and other unnamed storms. In addition to including previous storm related deaths, the prediction model includes the mortality impact of Puerto Rico's many public health challenges, and a particularly bad year for the Caribbean in general.

The excess mortality, then, is the number of deaths above and beyond what is predicted. It is specifically a measure of how much worse things were after Hurricane Maria than the previous 7 years would predict.