Here's asapm President Lew Ireland's reaction (his
head did not head hurt)
Both articles are valid, however, I think Glen may be being a bit of
a purist. The fundamental issue that the longer one waits to resolve
issues (long
duration projects) the more it
induces risk seems to be a valid comment. That is, the environment
can change and external issues beyond the scope of the project to both
positively and negatively impact the project. We tend to think of the "negative
impact" because that seems to be the major issue. "Positive
impact" is usually considered "luck."
The issue of "delays inducing risk" could be a great research
project to determine whether the simple formula or the complex formula
is the best. This discussion could be useful for asapm, and
should get more people, both members and visitors involved. The question
is, what
is
best for the project manager? Glen's
response
could be a good starting point for an academic research project.
Here's the response by Ilya Tirdatov, the original article's
author
I'd
like to thank Glen for his contribution, which seems to provide a solid
mathematical foundation to the general concepts outlined in
the article. In his response Glen said that ...
"This equation states there is a linear relationship between
the passage of time and the probability of something bad happening.
In fact the relationship between the passage of time and probability
of an external event is "not" linear as stated above, it
is exponential."
I would like to point out that, with regard to this statement, I never
claimed that there existed a linear relationship or that the formula
established its existence. In fact, I said exactly the opposite:
"The above formula is not, by any means, intended to express
all the complexities and eventualities of life in one primitive equation.
Even the most simple and "definite" activity would probably
be governed by a much more complicated set of principles, rules and
factors, than those that claim to bring its success into linear dependence
upon only one basic variable, being the time. The intent of this formula
is only to illustrate how, under certain circumstances, the time can
acquire critical significance, possibly outweighing many if not all
other considerations."
As to the term "linear" itself, I have applied it because
in this instance we are considering a certain limited period of time
rather than a perpetuity that would be reflected by an exponential
relationship. And Glen was absolutely right in saying that "...the
equation provided...represents a simple formulation of problem" because
that is exactly what it was meant to be!
The formula itself was provided
only as a matter of simple and understandable illustration of the
overall concept intended for practicing project managers, rather than
as a
comprehensive computational tool that may actually be used for forecasting
and planning. Apparently, unlike my formula, Glen's theoretical basis
can, indeed, have certain application in day-to-day project management
activities, and I am very impressed with the job he has done.
Bob Youker weighed in, pointing out that his Actors
and Factors workshop module, available on asapm's site
for more than a year, provides background and context for the type
of risks Ilya and Glen are now quantifying.
Bob's module is part of the World Bank Project Management curriculum
that is available to developing countries and others alike.
And Glen's response to the responses
(1) Lew's observation that the longer you wait the more likely something
bad will happen is correct in general, and is likely to be considered a tautology.
The delay induced risk assessment is part of "real options" theory
and used everyday in the financial markets and in some places here [Glen's place
of work] for
high
hazards
operations.
(2) Iyla's comments are also useful. One addition though is that for
the exponential distribution it is not for infinite time. In fact the
failure curve for simple lights bulbs (in the absence of damage) is
exponential. The waiting times at HOV lane lights is exponential during
rush hours, etc. so "theoretical" formula is probably not
the right understanding of this common model of real world activities.
Iyla's formula is linear because it has no second order terms, only
first order — linear — terms. The real world however is usually second
order non-linear, hence us physicists having to take the required 2nd
order partial differential equation classes as sophomores!!!
So the question is "do the readers of asapm have an
interest in such things, and if so, how can I contribute?"
Now it is your turn!
Please read Glen's article, and
then Tell Us What You Think!
