Re: Review of bayesian spam filters

On 24 Feb 2006, Brian Burton wrote:
> Anthony Campbell wrote:
> >On 23 Feb 2006, Nicolas Duboc wrote:
> >> Linux Weekly News has just published a review of bayesian spam
> >>filters. It includes SpamProbe.
> >>
> >>   http://lwn.net/SubscriberLink/172491/7eaf0d9defca131c/
> >
> >I was surprised at the relatively poor performance of SP here.
> >Insufficient training? I get NO false positives at all and not more than
> >one or two false negatives a day, sometimes none.
> 

[snip] 
> 
> Note also that since he started counting errors after training on only 
> 1000 messages (1/6) of his corpus he is really evaluating the filters on 
> how quickly they learn, not on what their steady state accuracy is. 
> That's fine but some filters might be more accurate early on while 
> others are more accurate with several thousand emails under their belt. 
>  Most testers train on 90% of the corpus and then evaluate the filters 
> on the remaining 10%.
> 
> That said I think it was a good article and it was obvious that the 
> reviewer went to a lot of effort to make a fair comparison.
> 
> All the best,
> ++Brian
> 

Thanks for these comments, Brian. From my considerable degree of
ignorance about how filters work I'd surmised myself that this might
explain the results. I certainly found that it took me some time to
attain the present level of efficacy. 

Incidentally, using pbl, my database has been stable at 19M for several
months now, which is a big improvement on the progressive growth to over
35M I had previously.

Regards,

Anthony

-- 
Anthony Campbell - ac-MeA/[email protected] 
Microsoft-free zone - Using Linux Gnu-Debian
http://www.acampbell.org.uk (blog, book reviews, 
on-line books and sceptical articles)



-------------------------------------------------------
This SF.Net email is sponsored by xPML, a groundbreaking scripting language
that extends applications into web and mobile media. Attend the live webcast
and join the prime developer group breaking into this new coding territory!
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642