A project manager plots the degree of certainty and complexity of a project along x- and y-axes to determine what type of project management approach would be the best suitable. The exercise shows that the project falls within the “complex” quadrant due to moderately uncertain requirements and highly uncertain technical challenges. What model is being used by this manager?

The Stacey Complexity Model is used by the manager to plot the degree of certainty about the complexity elements, including: requirements, technical challenges, or team skills. This model shows levels of uncertainty from low to high on both the x- and y-axes, or it may display levels of uncertainty on the x-axis and agreement levels on the y-axis. This two-dimensional model illustrates the progression of the certainty and agreement of complexity elements, which are plotted into categories such as simple or chaotic.