Re: Rule of Thumb?

[Rip Stauffer <ripstaur@vabch.com>]

JD asked, "By what method does one tell the difference between
professional management judgment and management lack of understanding of
variation?"

I would think that one method might be to ascertain whether the manager
in question has taken variation into account. If it had been possible to
take variation into account in making a decision, did the manager
recognize that, and use that understanding in reaching the decision? Did
the manager know, or was it a SWAG?

Some decisions are, ultimately, subjective; and these will have to be
based on judgment. Attempting to "objectify" subjective information in
order to ease this task cuts too much information away. Performance
evaluation and ranking schemes based on "objective" point assignments
are an example of this, as are many customer surveys based on Likert
Scales. 

There is no substitute for knowledge. What can you predict? Rules of
thumb should be based on both theory and experience. If they have proven
useful to the task at hand, use them (and keep looking for better ones,
of course!)

In a series of lectures to Ford statisticians, Deming once showed an
example of where eyeballing was the best early indicator of a difference
between three processes. I don't think he was against eyeballing, per
se; he was against eyeballing when there were better tests available.
And I think he was certainly FOR gaining enough profound knowledge to
know the difference.

Rip Stauffer
ripstaur@vabch.com
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