Hi Roxanne,
I've studied physics, with lot of mathematics (I used to say mathematics
was invented for the physicists), and was taught some lesson in measuring
and data. I'll summarize these ten tentative rules on quantities:
1. Data are but a quantified expression of an opinion (as also Charles
handy wrote on page 333 of Understanding Organisations), so always
inquire into the assumptions, the definitions, the supposed meaning or
the problem behind the data. (and always check the unit of measure);
2. Always be aware of the number of significant digits (so 1.4 + 3.14153
= 4.5 and not 4.54153 or 14 + 314153 = 31000);
3. There is a difference between "observables" and "system parameters".
The first are measurable through instruments, objective (temprature,
pressure, volume) the second belong to the world of models, subjective
(like: velocity of a molecule) and are also called variables. A model
attributes values to elements that are used in the (system) model to
explain the measurements.
The most dangerous system parameter is "profit", as it depends on a
number of choices in a model to somehow connect Expenses at time = now
(as in real money to suppliers) and Throughput at time = sometime later
(sold output, as in money from customers). The most horrible word, says
i, is costprice (never say costprice again!);
4. An American general (?) who said "There are lies, damned lies and
statistics";
5. Why we'd ever invent "quality" if we wanted only "quantity"? (I said
that).
6. A quantity only tells something about the person who measures ("look
who's measuring");
7. No universal law or principle was ever changed through measuring (not
even Heisenberg's famous uncertainty principle?);
8. There is no uninteresting number. (Proof: Suppose there were
uninteresting numbers, than some N would be the smallest uninteresting
number; now that smallest uninteresting number would be an interesting
number!);
9. "What I say three times is true". (And who said that?)
10. It takes a tenth rule to make ten tentative rules.
Greetings to the power of any number,
Jan Lelie
Drs J.C. Lelie CPIM (Jan)
janlelie@wxs.nl
LOGISENS - Sparring Partner in Logistical Development -
Mind@Work - est. 1998 - Powering Your Creative Mind(TM)
+ (31) 70 3243475 Fax: idem GSM: + (31) 654685114
--"J.C. Lelie (Jan)" <janlelie@wxs.nl>
Learning-org -- Hosted by Rick Karash <rkarash@karash.com> Public Dialog on Learning Organizations -- <http://www.learning-org.com>