Subject: RE: [Asrg] Fwd: Returned mail: see transcript for details

From: "Hallam-Baker, Phillip" <[email-masked]>
Date: Mon, 31 Mar 2003 09:18:58 -0800

> > Ignorance of a false positive may be bliss, but it isn't a good
> > thing.
> 
> Says who, the spammer or the spam target?
> My point is that whether a mail sender cares about a false positive
> is completely secondary to whether the mail target wants. 

If the message is a spam then it is not a false positive by definition. If
the recipient does not want the message it is not a false positive by my
definition.

I think that this attitude of trying to redefine false positive to mean spam
simply won't wash. It is being used to try to make the hard part of the
problem go away by pretending it does not matter. It reminds me of Douglas
Adam's laywers who try re-defining murder, re-evaluating muder and
eventually re-spelling it in an attempt to find a solution.

Fact is false positives do matter, and not just to the sender, by definition
a false positive matters to the recipient or it is not a false positive.

And in this particular instance 'by definition' means precisely that, it is
not used for emphasis. The definition of spam may be nebulous but false
positive is not.

	Phil 
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From: Vernon Schryver <[email-masked]>
Date: Mon, 31 Mar 2003 16:57:53 -0700 (MST)

> From: "Hallam-Baker, Phillip" <[email-masked]>

> ...

It's unfortunate that is mistaken.  "False positive" is not as frequently
abused as "spam," but it is often applied by bulk mail senders to any
filtering of their messages.

As others have pointed out, there is a genuine technical ambiguity in
"false positive."  Is it RD/TOTAL or RD/SPAM?  (for RD=rejected but
desired by recipient, TOTAL=total mail of all sorts whether rejected
or not, and SPAM=whatever that means).  This distinction may not matter
if RD is nearly 0 or if TOTAL and SPAM are about the same, but in
those cases, you're unlikely to want to compute RD closer than order
of magnitude.

If you pick RD/SPAM as your definition, then it is as foggy as "spam."

We need clear and concise definitions for

  - various sorts of mail that various people call "spam"

  - opt-out

  - unconfirmed opt-in

  - super-duper-ultra-double-nasty-impossible-to-do-confirmed-opt-in
     or whatever the bulk mail senders are currently calling the
     only sane way to do opt-in

  - consent

  - false positive

  - false negative

  - filter

  - DNS blacklist/blocklist

  - to forge (as in header or envelope "forgery" with the dictionary
     definition of "forgery")

  - mismatach between envelope or header From: and reverse DNS name
     of SMTP client (what many people mistakenly call "forgery")

Vernon Schryver    [email-masked]
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From: wayne <[email-masked]>
Date: 31 Mar 2003 20:24:30 -0600

> filtering of their messages.

Yes, there is some wiggle room about what exactly is a "false
positive", but I think it is somewhat of a red-herring to bring up
spammer's definitions.  Rule #1: Spammers lie.

> "false positive."  Is it RD/TOTAL or RD/SPAM?

For an example of "wiggle room", I have never consider a false
positive to be some sort of ratio.  It is a property of a piece of
email, just like a bounce or an email with 10 recipients are properties.

What you are asking about is what I would call the "false positive
rate". 

> We need clear and concise definitions for [list deleted]

Agreed.  

-wayne

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From: "Alan DeKok" <[email-masked]>
Date: Mon, 31 Mar 2003 21:37:41 -0500

Vernon Schryver <[email-masked]> wrote:
> or not, and SPAM=whatever that means).

  As an absolute number, false positive should be easy to define.  "I
went through my 'spam' folder, and I decided that 3 messages should
not have been put there."

  As a ratio or percentage, false positives are taken relative to the
desired signal, not to the total data, or to the noise.  So we have:

  MAIL   = number of emails you want to be marked as ok (not spam)
  JUNK   = number of emails you want to be marked as spam

  MARKED = number of emails actually marked as ok
  SPAM   = number of emails actually marked as spam

  FP     = false positives (number of "MAIL" in "SPAM", which should
           have been in "MARKED")
  FN     = false negatives (number of "MAIL" in "MARKED", which should
           have been in "SPAM")

  The ratio of false positives = FP / MAIL
  The ratio o false negatives  = FN / MAIL

  MARKED = MAIL - FP + FN
  SPAM   = JUNK + FP - FN

  Alan DeKok.

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From: Chuq Von Rospach <[email-masked]>
Date: Mon, 31 Mar 2003 18:30:42 -0800

On Monday, March 31, 2003, at 06:24  PM, wayne wrote:

>  but I think it is somewhat of a red-herring to bring up
but on the other hand, this lets people control discussions towards 
their own personal agendas by allowing them to define who the spammers 
are. If you don't like what someone is saying, call them a spammer, and 
since spammers lie, you can ignore what they're saying.

Convenient, but it leads to self-fulfilling discussions, not 
necessarily useful ones.

---

From: Vernon Schryver <[email-masked]>
Date: Mon, 31 Mar 2003 21:12:17 -0700 (MST)

> From: "Alan DeKok" <[email-masked]>

> not have been put there."

True, but such absolute numbers in isolation are merely boring noise.
Whether the number is 3 or 1,000,000 (eg. recently from AOL), it is
meaningless without some clue about the number of other messages.

> desired signal, not to the total data, or to the noise.  ...

>   The ratio o false negatives  = FN / MAIL

So say you and I, but not everyone else.  There is no canon that
sanctifies any particular definition of a "spam ratio," at least
not yet.