I always demand error bars.
Forecasts need to have error bars
21–30 of 165 posts
Re: Forecasts need to have error bars
#22Some thought it clouded the issue. For example, when a new treatment caused a 1% "improvement", but the confidence interval extended from -10% to 10%, it was clear that the experiment didn't tell us how that metric was affected. This makes the decision feel more arbitrary. But that is exactly the point - the decision is arbitrary in that case, and the confidence interval tells us that, allowing us to focus on other trade-offs involved. If the confidence interval is 0.9% to 1.1%, we know that we can be much more confident in the effect.
A big problem with this is that meaningful error bars can be extremely difficult to come by in some cases. For example, imagine having something like that for every prediction made by an ML model. I would love to have that, but I'm not aware of any reasonable way to achieve it for most types of models. The same goes for online experiments where a complicated experiment design is required because there isn't a way to do random allocation that results in sufficiently independent cohorts.
On a similar note, regularly look at histograms (i.e., statistical distributions) for all important metrics. In one case, we were having speed issues in calls to a large web service. Many calls were completing in < 50 ms, but too many were tripping our 500 ms timeout. At the same time, we had noticed the emergence of two clear peaks in the speed histogram (i.e., it was a multimodal distribution). That caused us to dig a bit deeper and see that the two peaks represented logged-out and logged-in users. That knowledge allowed us to ignore wide swaths of code and spot the speed issues in some recently pushed personalization code that we might not have suspected otherwise.
Re: Forecasts need to have error bars
#23Uncertainty quantification is a neglected aspect of data science and especially machine learning. Practitioners do not always have the statistical background, and the ML crowd generally has a "predict first and asks questions later" mindset that precludes such niceties. I always demand error bars.
Re: Forecasts need to have error bars
#24Re: Forecasts need to have error bars
#25Earlier quoted context omitted.
Ok, the 'reverse' of a confidence interval then -- I haven't seen a term for the object I described other than misuse of CI in the way I did. ("Double quantile"?)
You're probably thinking of a predictive interval
I say in theory because, in my experience in the tech industry, with the usual exceptions, uncertainty intervals, for example on a graph, are interpreted by those making decisions as aesthetic components of the graph ("the gray bands look good here") and not as anything even marginally related to a prediction.
Re: Forecasts need to have error bars
#26I 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
#27I 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?
Re: Forecasts need to have error bars
#28I 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
Statistically illiterate people should not be making decisions. I'd take that as a signal to leave.
Re: Forecasts need to have error bars
#29I 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
#30Two 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 "erro…
What you probably want is the standard error, because you are not interested in how much your data differ from each other but in how much your data differ from the true population.