SPAM statistic

Vernon Schryver vjs@calcite.rhyolite.com
Mon Nov 10 17:02:42 UTC 2003


> From: "Bolmerg-Berliner Ludger - Munich-MR" <lbolmerg@munichre.com>

> ...
> Over a period of 30 days about 81 percent of all SPAM mails were
> rejected.  The range of the percentages was between 71 and 91. The
> overall number of SPAM mails seen ranges from 133 to 187.  All numbers
> are calculated on a daily basis.  No false positives were seen.
> ...

200 mail messages/day or fewer is a small number from which to draw
conclusions.

The various spam ratio graphs at http://www.dcc-servers.net/dcc/graphs/
including http://www.dcc-servers.net/dcc/graphs/comp-rates 
combined with estimates of the true spam ratio can be used as a
consistency check for measures such as yours, or vice versa. 

If you think that 70% of mail is spam, than the 65%  in
http://www.dcc-servers.net/dcc/graphs/big.cgi?BIG=ISP-US-spam-ratio&BAK=comp-rates
implies that the DCC is more than 90% effective.

The trouble is that leaking even 10% (not to mention 30%) of current
spam rates is a lot.  

The trick to a mailbox that is 99.9% spam free (spam leaked/total spam)
is using several independent filters.  For example, 4 independent
filters each 85% effective are better than 99.9% effective overall.

Or you could believe the creative counting of salescritters for
various individual spam filters.


Vernon Schryver    vjs@rhyolite.com



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