RE: prediction

["Mack, Wayne" <wayne.mack@pec.com>]

I believe the following is an example of a false choice; the statement
presents the alternatives of continually revising judgment versus
disregarding the past.  I believe that knowledge of variation provides a
third alternative.

The major breakthrough of Dr. Shewart was to separate changes into assignable
causes, which one should react to individually, and common causes, which can
only be viewed as an aggregate.  It is equally incorrect to react to
individual instances of common causes as it is to ignore individual instances
of assignable causes.

Yes, prediction of the future is based on observation of the past, but one
should not change one's prediction with every sunrise.

Wayne Mack