Why Variance ?

Non-specific Quantitative Finance related chatter.
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doobs
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Why Variance ?

Post by doobs »

There is an entire field dedicated to robust statistics, here is a useful practical application. Where you can estimate higher moments without relying on any lower moments.

[url=/User%20Files/681/hwcv-092.pdf]Attached File: hwcv-092.pdf[/url]



The Skeptical eye usually leads to what I call "john wayne stats".

Can you please discuss an example of a use of a robust estimator that has been a disappointment? I'm not saying that robust stats should replace classical stats, all I am saying is that practitioners should be aware of its existence.
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kubrick
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Why Variance ?

Post by kubrick »

Example: in almost every case I've tried, I've gotten better OOS performance using (carefully hand-tuned, cleaned, etc) OLS regressions to robust regression methods.
Alpha male
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kubrick
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Why Variance ?

Post by kubrick »

PS, thank you for the paper, will certain read it!
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Rabid
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Why Variance ?

Post by Rabid »

In practice <3 median and interquartile range  for frugality reasons, but in analysis i usually resort to mean and mean absolute deviation for slightly better accuracy given that i have time to check for unusual implications
"Most of those people have no idea what you're doing, so no idea when to get nervous, so they get nervous a lot." LMAO
ZmeiGorynych
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Why Variance ?

Post by ZmeiGorynych »

Median of absolute deviation from [the median of the data] is a measure of dispersion/scale that is robust with respect to outliers.



Once I have computed that, I use it to identify the outliers, and after killing or thresholding them use standard linear-ish methods on what's left.



Of course a sceptical eye is always a prerequisite Smiley
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