Re: PDSA et al.

[John Dowd <johndowd@rcn.com>]

Seen in his context and time, Taylor's methods make some sense.  He was
developing methods to incorporate largely illiterate, agrarian based workers
into an industrial setting doing work they had not learned by observation or
apprenticeship.  

In that context his work revolutionized the work place.  Like all people he
had his biases and his blind spots.

Whether the methods he developed were 'scientific' or not is largely a
matter of definition.

Shewhart was the first person to divide variation into categories for the
purpose of economic decision making.

Do such things as special causes and common causes actually exist?  Again,
this is largely a matter of philosophical debate.  Shewhart skirted the
issue by defining them operationally.  That is, via a control chart.

He is not the first person to make note of the ubiquity of variation.
Wasn't it Heraclitus that said (essentially) 'one can not step twice into
the same stream' ?  That pre-dates Shewhart by a few centuries.

A part of Deming's work is based on the extension of Shewharts concept of
variation and it's application to non manufacturing processes.  Deming's
work was much broader than this and even his objection to merit ranking is
based on more than a simple view of variation.

For example he also points out the definitional problems and the difficulty
with operationally defining performance.   Operational definitions were
developed by Bridgman, not Shewhart.

John Dowd
johndowd@rcn.com