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# Not "Estimating" Chance of Success

Recently, while writing an article and later when revising Paul Newendorp's book,
it struck me as illogical to talk about "estimating chance of success." I've
used the phrase for many years, and now I don't like it.

Consider, for example, an exploration testwell. The well's possible outcomes are
"Success" or "Failure." We commonly use the computer science notation
of 1=Success (or True) and 0=Failure (or False). Thus, the outcome of nature is either 0
or 1. (Nature knows already; we don't yet know.)

"Estimating" is something one does in appraising or forecasting a value.
Assigning a probability to a binary chance event, which will happen or not, doesn't seem
like an estimation. Rather, the probability is representing the expert's degree of belief
about whether the event will happen. As a probability, this forecast—if one can call
it that—will *always* be wrong!

I suggest, instead, that you "assess" or "judge" a chance of
success (or probability of success).

If your job involves assessing chances of success, I recommend that you keep a
journal. Compare your judgments with what actually happens, whenever possible. Analyze the
data from time to time. This feedback is perhaps the best single thing you can do to
improve your risk assessments.

—John Schuyler, October 2000.

Copyright © 2000 by John R. Schuyler. All rights reserved. Permission to copy with
reproduction of this notice.