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Proving Which Spam Filters work Best
pirateninja writes "Dr. Gord Cormack decided to find and prove what the best spam filter is. In his study he looked at the major spam filters (DSPAM, SpamAssassin, etc.) along with those submitted by various academics. The results are quite surprising, with a previously unheard-of spam filter, which uses ideas from various compression algorithms, performing the best overall. He recently presented the results and methodology used in a presentation titled 'Spam Filters, Do they Work? and Can you prove it?'" Note that this is a video of his presentation.
The spammers actively try to subvert the more popular filters. That gives a lesser-known one a decided advantage, one which will go away as it becomes more popular.
As with most choices like this, factors such as ease of use, speed, and resource efficiency can overshadow selectivity. No system is perfect, so it's perfectly reasonable to go with a system that's pretty good if you already are using it, rather than switching to the latest cool thing.
I have found that using two dissimilar systems in a chain is quite effective.
Raise your children as if you were teaching them to raise your grandchildren, because you are.
The official tests of spamfilters were done in last year's TREC conference, you can read the writeup here (or pdf overview).
You can duplicate those tests yourself if you download the evaluation toolkit (GPL). It's a modular system where you can add a mail corpus (either one of the public TREC ones, or you can make your own trivially), and add a spamfilter package (there are 10 or so to download from the web, or create your own as per documentation).
There's also a video talk given at Microsoft research which should cover pretty much the same ground, if text mode is slashdotted :).
There's a new scheduled test towards the end of the year at TREC 2006.