[Spambayes] SpamBayes Outlook Plug-In Not Performing Well

[Jordan and Rory]

Hello, all.  My apologies if this has been answered before, or is a routine
question - I read through the FAQ and did several web searches without
finding an answer.

 

I have been running the SpamBayes Outlook (2002 SP-2) plug-in for many
weeks.  I have a training base of nearly 9000 spams and 800 or so hams.
Despite this degree of training, the filter is only achieving about 60%
success.  Many obvious spams receive a score of 0-2%.  The performance of
the filter doesn't seem to be improving as the database grows, either.  I
have retrained it from scratch several times, each time to no avail.

 

I recognize that my ratio of spams to hams is very high; however, a
different Bayesian filter I use at work has a similar ratio in its training
base, and still achieves 98%+ effectiveness.

 

What am I doing wrong?  What can I do to improve the percentage of spams
that SpamBayes catches?

 

Thanks in advance.

 

                                                            -Jordan