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A deep dive into missing data and the limitations of disaster databases.
If we want to reduce the risks of disasters, we need to track where they’re happening; what types of events they are; their human and economic impacts; and how these trends change over time.
High-quality data helps us see patterns in the data on factors such as increased resilience, climate change, and humanitarian response.
There are now several dedicated research groups that publish in-depth databases of disaster records.
One of the most widely cited is the International Disaster Database (EM-DAT) of the Centre for Research on the Epidemiology of Disasters (CRED). It is open-access and free and lets anyone dig into the specific details of each recorded disaster. At Our World in Data, we rely on EM-DAT as our main data source for disasters. It’s also used by organizations such as the United Nations, World Meteorological Organization, UNFCCC, and many academic researchers.
But no disaster database is perfect. Data is incomplete. Its quality varies over time. And some events are either unreported or hard to quantify.
That’s why it’s important to understand the biases and limitations of data sources so that they can be interpreted usefully.
Many of them are explained by EM-DAT itself in its documentation.
In this article, we explore several of these biases, which can lead to incorrect conclusions when analyzing historical trends.

The increase in the number of disasters is partly a result of reporting bias

Many smaller events in the past aren’t captured

  • We should be cautious about reporting increases in the number of disasters using EM-DAT
  • There are large gaps in disaster statistics, especially for economic damages
  • Heat deaths are poorly captured
  • Failure to capture the indirect impacts of disasters
This is a good example of a topic where you can tell whatever story you want depending on which metrics you choose.
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In this case, it's truly evident that data quality impacts reality. This happens with other topics as well, which is why I always say that you need to be very careful when analyzing graphics. As you know, graphics depend on the input data. I like to know how the data was acquired before drawing any conclusions.
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37 sats \ 5 replies \ @gmd 4 Jul
It seems like insurance companies would have pretty good data on this and they seem to be reducing their risk significantly.
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Do you mean they are downgrading the risks or that they are reducing their exposure to the risks?
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42 sats \ 3 replies \ @gmd 4 Jul
It seems like they are withdrawing coverage from a lot of areas like Florida due to hurricanes and fire risk areas in Cali...
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Yeah, but even there, you have to be careful about how to interpret that.
Monetary damages from natural disasters have risen a lot, but most of that is because of how much more stuff has been built in disaster areas.
Deaths and injuries related to natural disasters have declined, but that's mostly because of how much more we've spent on safer structures and better emergency response.
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69 sats \ 1 reply \ @gmd 4 Jul
No data, just hearing whispers/frustration from owners online whose coverage has either doubled or been completely withdrawn.
It seems weird to me to go from insurable to non-insurable unless the see something in the data.
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I'm not sure about California, but I recall hearing that Florida recently had a major insurance policy reform that sent premiums through the roof.
Beyond the actual quality of the data, you also have to think carefully about whether it's reporting the most relevant information to the question you're trying to answer.
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You're absolutely right. There may be hidden agendas behind data reporting.
Data quality is crucial, but it's only half the battle. The other half is ensuring the data is relevant to what you're trying to understand. In other words, relevant data might not be perfect data, but it needs to be suitable for the specific problem you're trying to solve.
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82 sats \ 1 reply \ @suraz 4 Jul
We are destroying nature and nature destroying us.
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Nature always wins in the end, so I'm not worried. 🤠
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16 sats \ 0 replies \ @OgFOMK 4 Jul
I hate this question because it is not important to our life as humans. If we are not learning from the millions of years of existence then we are not going to learn from a few days of data accumulation.
It's an excuse for central planning which causes much suffering.
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Nature has always been very wise, natural disasters occur when we human beings abuse its resources, leaving destruction and neglect in our wake.
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11 sats \ 0 replies \ @Roll 4 Jul
it s hard to tell if there is more or not: -as science do not have yet all the parameters to mesure or willing to take some in account. -and the date of this analysis. An 100 years vs earth between 4 and 5 bilion years old
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Just the other day a Heat Wave took out a boy in South Mountain (a few miles from me).
I believe there are at least 5000 heatwave deaths per year around the world. I think this is down from historical standards, but it still is a natural disaster if it happens at scale & at once.
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definitely some of the increase can be attributed to better reporting and higher population densities, the underlying factors such as climate change and environmental degradation play a significant role in the rising frequency and severity of natural disasters.
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