Moving Beyond the Triple Constraints
Dave Garrett recently wrote on the concepts expressed by Aaron Shanhar in his book, Reinventing Project Management. The gist is that the common triple-constraint model of managing cost, schedule, and scope is not enough. As I like to put it and in Goldratt’s words, necessary but not sufficient.
I have not yet read Shanhar’s book, but have a few initial thoughts based on Garrett’s description.
The notion feels right. I have observed a few specific behaviors that may come about because of the framework of incentives set up by the traditional approach. First, quality assurance seems to be an afterthought or necessary evil in many projects, if it happens at all. I agree with the notion that the triple constraints are efficiency-focused. They set up incentives to meet the requirements, even if those are the bare minimum. Many times, scope is reduced as a result of cost cutting efforts, and they are looking for whatever will provide barely satisfactory results. Activities are dropped without a thorough analysis of what the impact on quality, team morale, etc. might be.
Second, I have known many project managers to define success as sticking to the requirements, even if they are very bad requirements. There’s no incentive to put a lot of effort into quality requirements if a project manager knows they will still have met scope, schedule, and budget. In other words, you can have a failed project which meets all three constraints. Interesting….doesn’t sound like success criteria.
I agree we need a better model with which to think about projects holistically. I look forward to reading Reinventing Project Management, and learning more.
Sep 28th, 2008 at 11:42 pm
The ‘triple constraint’ looks backwards, not forwards. That is, it is about the inputs, not the outputs. The only thing of interest to a project recipient (even if they don’t know it) is the value (in NPV terms, if you must) of the project at its completion date. So, if you must increase the investment, or change the schedule, or scope (aka quality) it can only sensibly done in the light of getting the best value outcome.
I used to be involved in developing retail centres our only consideration was to open for a major shopping period: usually Christmas: so open by the first week in December, or just prior to Easter; if we missed the millions of dollars that would flow through the centre at that time, cost, schedule and scope didn’t mean a jot, and the three inputs were juggled, usually by increasing the investment, to get the value of opening on time.
So, sure, the PM has three corners to attend to: what he’s doing, when it’s to be done by, and how much he can spend to do it; but its all for the value to be produced. The value may be a stream of income, non-monetary benefits, or costs avoided, but they are the target of projects, not the project itself, per se.
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Sep 29th, 2008 at 12:17 pm
Thanks for the comment David! I think Shenhar agrees with you. He talks about how the traditional triple constraints are focused on efficiency only.
Josh Nankivel
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Oct 9th, 2008 at 7:28 am
I agree with David. Construction related projects have a very different set of priorities and dynamics from other type of projects. Quality is often determined by technical specifications set externally. Cost and schedule are often conditional on finishing by a certain date or within a certain budget at all costs. The value of the Project is Zero until it is finished and deliverables rolling.
In that respect, it is a more primitive environment to be working in! I guess that is why you see PMs shifting from industry to industry, with the exception of Construction PMs, which seem to be fairly specialized.
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