R. Scott Perry wrote: > As you point out, this isn't an easy task (it's harder than determining the > spam capture rate, which is actually complex). The main problem is getting > a diverse set of legitimate E-mail. Also, it depends on your definition of > false positives -- for example, every legitimate E-mail (whether or not it > is marked as spam) gets read here (because of the business we are in, we > must receive all E-mail, and not block any -- instead, we use Declude > JunkMail to sort out the spam), so some people would (incorrectly, in my > opinion) say we have 0% false positives.
Agreed. If one is to accept *all* inbound mail, one can thus claim exactly 0% FP because there are no "positives" at all :) (A company -- corporate or ISP -- having no antispam whatsoever could spin this as a marketing advantage!) Conversely, if one blocks *all* inbound e-mail, the [*apparently*] very same 0% FP ratio applies since no legitimate e-mail is falsely flagged as spam -- because no e-mail ever arrives... This is why it is important to have a precise definition of exactly what is an FP ratio in terms that are scientifically (or at least statistically) founded and accepted by the antispam "industry". I believe that you have explained this most satisfactorily in your earlier postings. > >More to the point, am I also correct that the aforementioned > >"single-criterion/reject-at-the-envelope-level" solution *cannot* ever give > >me *any* measurable FP ratio? > > Correct. > > -Scott Thanks; this is what I was trying to confirm for myself. There are a few valid ways to "rightfully" reject inbound mail based on the pre-DATA envelope transaction and I think that we both agree on this. My point was and is that by doing so, you cannot derive an FP ratio at all. This may not matter to some mail admins and this is fine (for them) as it is their choice, informed or not. Speaking for myself only, I'd rather be informed :) Guy -- Guy Isabel <[EMAIL PROTECTED]> To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
