Estimation Skills

Nov 06, 2010 20:46

I get annoyed by download information that makes utterly useless stabs at how long something is going to take to finish ( Read more... )

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dougs November 6 2010, 20:56:23 UTC
I think http://xkcd.com/612/ is appropriate here.

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andrewducker November 6 2010, 21:15:38 UTC
Exactly!

I don't mind estimates varying during something happening - but the sheer amount it varies is silly, we should be able to deal with it better than that. Averaging over a percentage of the operation time, rather than the last couple of seconds, and taking into account long-term averages both seem so obvious I can only assume that the people who write these things have better things to spend their time on.

Being a developer myself I know that stuff like that would only get written if someone working on the code got fed up with it themselves and decided to write a better estimator, and then snuck the code in when nobody was looking.

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andrewducker November 6 2010, 21:55:56 UTC
I'd like to know what the %^&%^& takes a factor of 60 times longer on one version of Linux than another...

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ciphergoth November 7 2010, 08:42:14 UTC
TBH I suspect the most reliable estimate wouldn't have any recency bias at all, it would just estimate based on average speed.

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drdoug November 7 2010, 10:20:57 UTC
A simple arithmetical mean might be misleading, though, particularly if your throughput is highly variable - a geometrical mean ought to be more accurate. And - particularly at the start of a long download - it'd be prone to the sort of wild jumping around that XKCD cartoon is sending up, unless you have some clever damping.

Some recency bias might make some sense, though - with this particular download, my bet would be that it finished closer to the 4h10m than the 5h estimate, and certainly less than 7h3m, because the tubes will be emptier late at night than they were over the course of the download up to the time of the OP, which spanned the UK peak net congestion time. (My fatalistic estimate is that it crashed out, or paused for some user intervention, shortly after andrewducker went to bed ( ... )

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ciphergoth November 7 2010, 10:25:22 UTC
We need data!

Steam should be collecting the data they need to get this right, they're in an excellent position to do so.

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