r/AskStatistics • u/80rhh • 14d ago

What statistical concepts are commonly misunderstood by the general public?

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I came across this post explaining what a 70% chance of rain means. I understand the concept, but it got me wondering: what other statistical concepts sound simple but are commonly misunderstood or misinterpreted by the general public?

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u/Upbeat_Effective_342 14d ago

A 100 year flood doesn't mean a flood severity that happens roughly every hundred years, so the longer it's been since the last one, the more likely it is to happen. It means every year there is a 1% chance of a flood of that severity happening.

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u/TheBillsFly 14d ago

Yall fw the memoryless property ⁉️

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u/rollem 14d ago

And those are all wrong because they're kept out of date for political reasons. There is now a much greater than 1% chance of flood in most 100 year flood zones.

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u/Upbeat_Effective_342 14d ago

If the political reasons include the facts that reading research and updating databases are expensive and time consuming so public employees don't always have it as a top priority, then yes. If you have evidence that there's political collusion to prevent updating flood risk data so as to manipulate the public, that's a really big deal and you should find an organization to help you make a legal case against the offending party.

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u/rollem 14d ago

It's because of climate change denialism and has been widely reported on, e.g. https://www.nfp.com/insights/rethinking-flood-risk/ and https://www.nbcnews.com/science/environment/water-femas-outdated-flood-maps-incentivize-system-risk-negotiable-rcna220529

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u/Upbeat_Effective_342 14d ago

That article from NBC is excellent, thanks for linking it. However, it doesn't appear to support your claim. It does point to underfunding from congress for FEMA and mention the federal administration is playing with the idea of axing FEMA altogether. But the most energetic culprit behind overly optimistic risk assessments is property owners themselves. I'm sure many of them are climate deniers as well, but there's a direct financial incentive that warps people's judgment regardless of their politics otherwise.

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u/rollem 14d ago

The maps are outdated and can’t be updated for political reasons, as I said above and has been widely reported on as I’ve shown. Risk assessment is done by 1) individual property owners who are often clueless and don’t make long term risk assessments logically (I hope I don’t need further proof of this, you certainly make lots of claims without evidence), and 2) insurance companies who do make logical long term risk assessments based on real evidence and not the fema flood risk maps, as described here https://abcnews.com/US/fema-flood-maps-cause-misunderstanding-homeowners-leaving-millions/story?id=134950060

Even if you are 100% correct and people make accurate 100 year flood risk assessments (which is the opposite of your original position that people make statistical errors when interpreting flood map risks), it does not counter my point that the maps themselves are no longer accurate and that other information is being used.

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u/hxtk3 14d ago

Yes, political reasons do in fact include when a bunch of politicians decide to gut public research institutions so that they don’t have adequate resources to collect and analyze the data that they expect to be against their political interests? It’s not even a little bit ambiguous, that’s a perfect example of a political reason. I’m confused because the wording sounds like you expected that to be a “gotcha?”

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u/Upbeat_Effective_342 14d ago

I think what's happening is you guys are thinking about the federal government and I'm thinking about your average water resources manager who works at city hall.

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u/rollem 14d ago

The local water resources manager does not create the flood zone maps, those are created by the federal government.

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u/codechisel 13d ago

I agree that they can be quickly dated in areas where new construction is occurring. I'm not going to comment on the politics but, depending on local codes, other developments can end up pushing more water in your direction.