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Understanding the Triple Constraints |
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Much has been said about the triple constraints. What are they? What is included and why? This article addresses the
basic triple constraints. We intended to give beginning Project Managers and future
exam takers some background into the “what and why” it is included in the basic
exam material. The
Exam The first thing that one
should ask themselves in studying for a project management certification exam
is “is this critical”? Could one assume that because the triple constraints
are not well defined in the official body of knowledge, might you only need
to know that they exist? Could this be one of those subjects that fall into
the mile wide and inch deep category for your certification? If you are still
reading, then you must have concluded that you urgently need to understand triple
constraints. Often you will hear
about the time, cost and scope. It is the author opinion that this is the
true triple constraints. You may hear that Quality and Risk may be other constraints.
The Classic
Three Lets talk about the first three, Scope, Time and
Cost. If you increase scope, it seems pretty clear that the time and/or cost
will increase. If you increase cost, you may be able to decrease time. And
decreasing scope will most likely decrease cost/time. While we can cite lots
of examples to the counter, this is generally true on most projects. Quality Now let us look at
quality. Many people confuse quality with grade. To help define the
difference, I use the example of a new car. Take a 1960 Mercedes and compare
to a 1960 VW bug. Which
has higher quality? Most people will pick
the Mercedes. But if I said, take that car, drive it on the beach to a
bonfire, and have a 19 year old college student maintain the car, you would
find an unhappy customer with a broken car. In this case, the features of the
car didn’t match the customer’s needs. Swap the example and
take the VW to the opera and you end up with an unhappy customer as well. So, modern quality is often
defined as “meeting the stated or implied needs”. In the above case, you find
that the implied need of the differing customers resulted in two different grades,
not different quality. Both cars have high quality for their customers, but different
grades. Trading
Quality So, let us apply this it
a project and see if we can trade quality for scope, cost and time. Use the
project of creating a heart pacemaker. Can you sacrifice the customer’s
expectation (stated or implied needs) and still be ethical? You could change the
scope and or requirements of the pace maker, but if you fail to meet the
expectations of the customers, your customers would die. If you reduce the
battery life of the pacemaker and disclosed in on the spec sheet, you are
managing scope. If you do not meet the requirements and fail to disclose it,
it is considered fraud. So managing the
expectations of the customer is managing the scope of the project, not the
quality. Ultimately the PM should deliver a product or service that meets
expectations or change the expectations. Risk Now let us look at risk.
The other often quoted triple constraint. In modern risk theory, the risk and
cost is closely tied together. The interesting thing is that it is not
linear. High risk results in a low initial cost, but if the risk is realized,
the project costs can be high. Low risk typically means increasing cost at
the start of the project, with the expectation that the cost will not
increase as much over the life of the project. Summary So, cost/time/scope relates
in a see-saw fashion, where one goes up and the other goes down in a related
fashion. Sacrificing quality is unethical (because if you disclosed the
change in expectations, you would be changing scope) and risk is like a swing,
where you are trying to find the optimal point. Too conservative, costs
increase. To aggressive, costs increase. I hope this is helpful
in understanding the relationship between Scope, Time, Cost, Quality and Risk.
It is up to you to see make your judgment of the true meaning of triple
constraints. The true understanding
of the triple constraint and its value is in managing projects. If you find
that you are trading quality and risk, keeping scope, cost and time constant,
then you have defined your grade of project management. Best wishes in your
journey Mike Graupner, PMP |
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