Re: Cause source - system v. employee

[Stein Smaaland <smaaland@sys.no>]

Dear Denizens!                 Oslo, March 22nd, 2002

Please allow me to jump into the dialogue between
Wayne and Steve, with thoughts more based on my
Deming learning (since very late 1980s) and my
on-going projects and basic philosophical studies,
than my natural science background from the 1970s;

Wayne says:
...My understanding of control charts is that the
only time that a cause for a variation can be
objectively identified is when a special cause has
occurred.  The criteria used is timing, what
happened just prior to the change in the data?...

Two points;
1) Refering to the criteria TIMING, perhaps we also
should include (ref. David Hume);
a) contiguity on space and time 
b) succession
c) regularity?

2) Can ANY cause be OBJECTIVELY identified?
Isn't probability essential?

Wayne continues:
... In the case of common cause variation, however,
the result of the analysis is a hypothesis and further
experimentation is required to make an objective
determination.  This is done by correcting the
suspected cause and verifying that a special cause
variation occurs on the control chart immediately
following the change...

One point;
3) Sorry I do not understand why a special cause
variation should occur immediately following
the change? Have I missed something?

Still learning
Deming Scandinavia
Stein
(stein.smaaland@deming.no)
*** The Quality of a SYStem ****