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The real caveat is that 538 was a Monte Carlo model, and is only as good as its inputs. "Here's what the current spread in polling numbers is *given our model and the current polling and their reported uncertainties.*" Polling uncertainties are themselves computed under certain models, and those models are subject to errors. I don't think 538 hid this, but it's a difficult caveat for people to reason about because the sorts of modeling errors that have the most influence usually represent "unknown unknowns".

by this_user4 hours ago|

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Building a model for predicting the ultimate winner of a US presidential election is particularly difficult, because you are dealing with noisy input data and nonlinear effects, i.e. just a few thousand votes in a few key states can completely flip the outcome. If you then have poorly calibrated polls with a large margin of error, there is really nothing much you can do.

On the other hand, it does raise the question how valuable the 538 models for something like this really are if the outcome is a coin flip anyway.

by ngriffiths3 hours ago|

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Exactly, and correlated errors, where a polling error in one state predicts similar errors across the board.

I disagree that it's all pointless though. Most basically it's smart for campaigns to have a good model and let that inform strategy where appropriate. Since the president is a big deal other people's decisions are also impacted, and in the long run it pays to have good predictions of those chances. Also, the outcome sometimes is fairly certain and that isn't always easy to see.

by bryanlarsen5 hours ago|

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Regularly referring to that ~30% spread as "one polling error" made this a lot more understandable than most statistics for many people.

by bsimpson7 hours ago|

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That's a core mechanic in games like Dispatch.

People don't like seeing a 95% chance of winning and then losing. The game tweaks the odds, so certain thresholds become gimmes (something like "if the displayed odds are better than 75%, treat them as 100%").

by tantalor6 hours ago|

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That's stupid. That would piss me off.

by greycol1 hours ago|

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Seems weird that it would piss you off, if you were really that invested in the cold hard stats you'd know that if it was fair rng you could still have been the 1 in 100,000 player that got lucky on 75% 40 times in a row.

by a_t485 hours ago|

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Fire Emblem does something complex with averaging random numbers to do the same thing - a 95% chance to hit becomes 99.5, and the reverse for low percentages.

by lmm3 hours ago|

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Conversely weather forecasters report a 40% chance of rain when the actual chance is 10% or similar.

So I have a bit of sympathy for people who don't have a good intuition for probabilities, given that the world is constantly gaslighting them.

by FireBeyond6 hours ago|

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> Discussion of stats models is always complicated by the fact that a lot of people will read "30%" as a "no" prediction and claim your model is wrong if the thing happens.

I've even heard things like "70% chance of Hillary winning means she gets 70% of the votes!" (and tangentially, my far-too-long argument with someone on Reddit who insisted "there is no way in hell 50% of the people in this town make above the median income"...)