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88 CRITICAL PATH, CRITICAL CHAIN, UNCERTAINTY

From what I can fathom from his discussion on resource constraints, some
method such as the familiar resource leveling technique (see Chapter 4.1) must
be employed. However, the use of resource buffers in the critical chain method
does not insert actual resource contingency (no resources are assigned to the re-
source buffers), but rather just inserts a time contingency prior to the scheduled
resource usage. This gives me cause for concern. If we acknowledge that we
should assign the shortest reasonable duration to tasks and then add schedule
contingency, then doesn’t the same philosophy apply to resource effort? That is, if
we reduce the task duration and associated resource effort to get the fat out, then
surely we have to add some resource effort contingency to the plan. Otherwise,
we go blindly into our projects thinking that we have budgeted enough resources
and have no reserve to work from when the effort (as it surely will at times) ex-
ceeds the plan.

This, therefore, is a serious flaw in the critical chain theory. It effectively ad-
dresses risk and contingency for schedule, but ignores risk and contingency for
resource effort and cost.

Other Goldratt Ideas

Goldratt correctly points out that people are often moved to inflate their task esti-
mates because of the poor communication of the status of predecessor tasks, and
when their task will start. Goldratt suggests that a regimen for monitoring and
communication, that would provide for 10-day, 3-day, and 1-day advance notifica-
tion, would alleviate this problem. This just makes good sense, no matter what the
PM approach.

Finally, Goldratt teases us with some good thoughts on the cost benefits of im-
proved schedule performance, but falls short of presenting a complete and cohe-
sive treatise. Without saying as much, Goldratt starts to address what we are now
calling Project Portfolio Management. In view of the current hoopla regarding
this subject (see Chapter 9.1), I would like to see a follow-up on his points, specif-
ically relating them to project portfolio management issues.

Disagreements and Fallacies

I have to admit to a chronic weakness—that of seeing both good and bad in al-
most anything. Hence, while I support the general concept of shared buffers,
as forwarded by the Critical Chain Project Management method, I can’t help
but see numerous fallacies in some of the basic premises. What is especially
disturbing are the inconsistencies and contradictions, some of which have been
already noted.