more on Spam Controls Imperil E-Mail Reliability

[David Farber <dave () farber net>]

------ Forwarded Message
From: Tony Lauck <tlauck () madriver com>
Date: Tue, 01 Mar 2005 17:12:46 -0500
To: <dave () farber net>
Subject: Re: [IP] Spam Controls Imperil E-Mail Reliability

Performance Requirements for Effective SPAM filters.

Some of the recent discussion about SPAM filters has caused me do do a
"back of the envelope" analysis of their required level of performance.
I take the user perspective, as I have the data from at least one user
(me) and the analysis is very simple. Taking the global perspective
would be much more difficult and would require a game theoretic analysis.

I suggest the following specifications:

      False negative rate <  0.05
      False positive rate <  0.0000001

For some years I have been keeping statistics of all SPAM messages that
I receive. (I have instructed my ISP to label but deliver SPAM
messages.)  I currently receive approximately 100 SPAM messages each day
and would consider the problem effectively solved if it could be reduced
to 5 messages.

Several years ago, I received a short email message from an unknown
person.  This message led to an email exchange followed by many years of
profitable consulting work, perhaps 10,000 hours in total.  Some rough
timing shows that I can discard SPAM messages at the rate of 1000 per
hour.  Hence the false positive requirement of 10-7.

I would be more than amazed if these performance numbers could be met. I
suggest that spam filters are a dead end path. ISPs and their users
would be better advised to forget about filtering spam messages, saving
their efforts instead for tracking down and eliminating spammers by
whatever means are necessary.

[Dave, please reply to this email, even if you choose not to post it.
Otherwise, I will need to telephone you to see if it was filtered out.
:-) - Tony]


------ End of Forwarded Message


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