Re: Spam fighting

[Eliad B <debian.bash@googlemail.com>]

On 07/05/2010 04:19 PM, Bjoern Meier wrote:

hi,

2010/7/5 Eduardo M KALINOWSKI <eduardo@kalinowski.com.br>:
. No system will ever be 100% accurate
  

and filter all spams.
    

Right. But less then 99.8% - for a private system (which the list is
not) - is not tolerable. Can the list track how spam is blocked and -
maybe - an overview how effective this is (like graphs over a few
periods)?

greetings,
Björ

Hi,

just some obvious calculations:

assuming that all blocked emails are indeed spams, we have:

blocked-spams / all-spams = blocked-mail / ( blocked-mail + not-blocked-spam )

So,

blocked-spams / all-spams = 0.95 / ( 0.95 + 0.05 * (not-blocked-spam / legitimate-mails) )

Y = X/(1-X) * (1/A -1)

in which,
A: blocked-spams / all-spams
X: blocked-mail / all-mails
Y: not-blocked-spam / legitimate-mails

Assuming the goal is to have blocked-spams / all-spams higher than "0.998", it can be shown that (not-blocked-spam / legitimate-mail) must be less than 0.038. And I think it is.

Conclusion: The system is good enough.

Yours truly,
Eliad