All Geek to Me

September 27, 2008

The Triangle Fallacy

Filed under: Geek Stuff — britinla @ 7:00 am


Our  CIO frequently refers to the project management triangle. He will say that if he is given the functionality and resource/cost axis of the project, then the executives cannot choose the time-scale; because with two sides of the triangle given, the third is outside of the realm of specification. I do not accept  this model, for it fails to take into account a fourth variable; the triangle is wrong because it fails to consider quality. If you look at a project not as a triangle, but as a quadrangle you can see that management can impose time, resource/cost, and functionality upon developers and if quality is sacrificed all three constraints can be met. 


The triangle is a wonderful theory, like universal peace. It assumes that quality is an unchangeable absolute from which nothing can can be removed. In the real world quality is not a diamond  under a tin blade. Sacrificing quality to meet a plan is  short sighted, yet frequently used approach to resolving the problems of a project that is failing to meet its goals. I have seen software projects slip and then be brought back onto schedule by reducing the time alloted for testing. I have all to often seen resistance to code reviews justified by pointing at a schedule that is looming and the accompanying claim that there is not enough time. 


There is always enough time for quality. It is quicker and cheaper to correct a defect at the design stage than it is is in the coding stage. It is quicker and cheaper to correct a defect at the coding stage than it is in the testing stage. It is far cheaper and quicker to correct a defect at the testing stage than in production. 

Projects are not triangles. Projects are quadrangles. The Project Manager must start start with the line that represents the required quality;  then circumstances will dictate which of the other three variables are given. Sometimes a project must be delivered by a certain date with the team at ones disposal; thus constraining the functionality, or any one of the other available combinations. If the quality is not the first line in the sand it will be overlooked and projects will ignore it, compromising it to that short sighted triangle.



  1. I find your analysis lacking, as it fails to incorporate string theory, which predicts 26 dimensions. Since most of these extra dimensions are rolled up in infinitesimally small “strings” their effect upon the universe or in this case, project, are usually ignored. However if they were properly accounted for, you would see why projects over-run, cost too much and deliver a poor product.

    Comment by @mmonyte — September 28, 2008 @ 12:16 pm

  2. @mmonyte’s contribution can perhaps be summarized into a Fifth Element: risk.

    Risk may affect scope, and it may not. Risk may affect time, and it may not. It is part of the whole; we then find ourselves with a Project Management Pentagram.

    It is no coincidence that this particular shape possesses the same number of sides as a pentacle possesses points. This nod to the mysterious energies of a seemingly random universe suggest that a prudent Project Manager ought to prepare well by donning the protective symbol before deploying a project.

    Comment by ilegirl — September 28, 2008 @ 8:24 pm

  3. I have to say that quality is the first one to suffer, usually you fix the cost and the time, and then the quality will be affected (cutting functionality is a form of cutting quality). I have published an article about the project management triangle, and in it there’s a small paragraph that goes: “Normally this occurs when costs are fixed and there is a definite deadline for delivery, an all too familiar set of circumstances. Then, if the scope starts to creep you are left with only one choice – cut functionality. This more common than you might think, in fact its more common than not!”

    I guess we can all relate to that!

    Comment by PM Hut — February 10, 2009 @ 8:48 am

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