Enter the Pyramid

I propose a model that represents the first four variables as the four sides of the base of a pyramid. We'll assign extensive properties to the sides so that the lengths are meaningful. Note that this is different from the Davis tetrahedron model, in which the attributes occupy the vertices.

For simplicity, let's assume that all sides of the base are of equal length, so that the base forms a square. This is reminiscent of Max's star, except that I have moved the attributes from the corners to the edges. Of course, these lengths can be independently adjusted, so the base is actually an arbitrary quadrilateral. Conceptually, however, I lose nothing by assuming for now that the base is a square.

Now let's redefine the length of each side of the base. I will also adjust the terminology slightly to reflect more accurately what the sides represent. Bear with me, and you will see why:

• Scope. More "things to do" represents a larger scope, so the length of this side increases as the scope increases.

• Quality. Higher quality standards mean a tougher job, so the length of this side increases as our quality metrics increasein other words, as we "raise the bar" on quality.

• Speed. This is our way of capturing the time element; we increase the length of this side as the speed increases. Conversely, the slower you gothe more time you havethe shorter this side becomes. Completing five function points per month is harder than completing two function points per month; think of this side as work accomplished per unit time.

• Frugality. (Max suggested this term instead of my original parsimony.) When we consume fewer resources, we are being more frugal. So higher frugality corresponds to a longer length for this side. If we use up more resources, then this side gets shorter.

Notice that if I use these definitions for scope, quality, speed, and frugality, the project becomes easier if the sides are shorter. That is, the project is easier if we do less, lower our quality standards, proceed more slowly (take more time), and can afford to be less frugal (have more resources). Thus all four variables "move in the same direction."

Note also that with these definitions you increase your profitability as you increase the area of the base. This is because the value of the product goes up as you make it bigger, better, and get it sooner, while at the same time are the most frugal in producing it. Maximizing value while minimizing cost optimizes for profitability. It's perfectly logical that attempting to make our profit larger also makes the project harder and more risky.