From: Harvey Newstrom (mail@HarveyNewstrom.com)
Date: Wed May 29 2002 - 19:47:11 MDT
On Wednesday, May 29, 2002, at 07:57 pm, CurtAdams@aol.com wrote:
> It doesn't have to be consistent; probabilistic is enough.
Wrong. People argue that blacks are more likely to commit crime. This
does not mean that we can identify criminals by skin color. Some blacks
aren't criminal, and some criminals aren't black. Worse yet, even if
blacks are shown to have a higher probability of criminal behavior, it
is still true that most blacks are not criminal. Any correlation with
"black" meaning "criminal" would be inaccurate more often than it would
be accurate.
This is why this is "incorrect". I don't mean "politically incorrect".
I mean mathematically, you get the wrong answer more often than the
right one. This is not acceptable for the basis of any group-based
judgment
>>> "People who have been nice to you in the past", after all, is
>>> just another group.
>
>> Incorrect. "People who have been nice to you in the past" is a group
>> derived from specific measurements of individuals. Only individuals
>> who
>> were nice are in the group. Any individuals who were not nice are
>> excluded. Group membership derives from the judgment. The group is
>> an
>> accurate demarkation of the determinate trait.
>
> Right. So are groups demarkated by skin color, eye color, religious
> preference,
> ice cream flavor preference, or whatever. Group identity is useful to
> actors when it correlates with some behavioral/ability characteristic of
> note - for whatever reason.
But you are making false assumptions. Do the math and calculate your
error rate. If 10% of whites are criminals and 20% of blacks are
criminals, that means your fear of a black person being a criminal is
wrong 80% of the time. What good is a "measurement" or
"behavioral/ability characteristic" if it is wrong four times as often
as it is right? Furthermore, if blacks are only 10% of the population,
there would be more white criminals than black criminals. Any security
measure that focused on blacks would only be aiming at a smaller
percentage of criminals while ignoring the larger percentage. What good
is a statistical correlation that emphasizes the lessor possibilities?
>> Using group membership to inform actions is the exact opposite of this
>> approach. People are assigned to groups first without specific
>> measurements being made of the individuals.
>
> No, you have to measure *something* or you can't assign a group.
But in the first case you have directly measured traits that are
accurate for all members of the group. In the second case you have
unmeasured traits that are not accurate for all members of the group.
The first group defines accurate information. The second group
statistically allows possibilities that might or might not really
exist. You cannot treat these sources of information as equally valid.
One is fact, the other is untested theory. It is OK to pursue the
theory for further investigation, but we can't base any important
decisions on it as if it were factual.
-- Harvey Newstrom, CISSP <www.HarveyNewstrom.com> Principal Security Consultant <www.Newstaff.com>
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