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Forecasts need to have error bars

andrewpwheeler.com

1–10 of 165 posts

Re: Forecasts need to have error bars

#5
I have, in my life as a web developer, had multiple "academics" urgently demand that i remove error bands, bars, notes about outliers, confidence intervals etc from graphics at the last minute so people are not "confused"

Its depressing

Re: Forecasts need to have error bars

#7

The interesting example in this article is nowcasting! The art of forecasting the present or past while you're waiting for data to come in. It's sloppy science / statistics to not haven error ranges.

Not easy to always say what the benefit is: if you present in-model uncertainty from a stochastic model that might still say nothing about an estimation error vs the actual process. For forecasting to show actual uncertainty you need to be in a quite luxurious position to know the data generating process. You could try to fudge it with a lot of historical data where available - but still...

Re: Forecasts need to have error bars

#8
Two things I think are interesting here, one discussed by the author and one not. (1) As mentioned at the bottom, forecasting usually should lead to decisionmaking, and when it gets disconnected, it can be unclear what the value is. It sounds like Rosenfield is trying to use forecasting to give added weight to his statistical conclusions about past data, which I agree sounds suspect.

(2) it's not clear what the "error bars" should mean. One is a confidence interval[1] (e.g. model gives 95% chance the output will be within these bounds). Another is a standard deviation (i.e. you are pretty much predicting the squared difference between your own point forecast and the outcome).

[1] acknowledged: not the correct term

Re: Forecasts need to have error bars

#9

I really thought that this was going to be about the weather.

Same, but in a human context, are mundane atmospheric events so far off today that error bars would have any practical value and/or potentially introduce confusion?

For this reason I really enjoy reading the text products and area forecast discussion for interesting weather: https://forecast.weather.gov/product.php?site=NWS&issuedby=p...

Re: Forecasts need to have error bars

#10
post #5

I have, in my life as a web developer, had multiple "academics" urgently demand that i remove error bands, bars, notes about outliers, confidence intervals etc from graphics at the last minute so people are not "confused" Its depressing

The depressing part is that many people actually need them removed in order to not be confused.
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