Effective Corrective Action: The initial/envelope model for managing projects
Summary Two of the most important dynamics in planning for projects are the “rookie-professional” up-to-speed delay for new hires, and the “undiscovered-rework” feedback loop. A recent report [Nevison, 2015] used a project model that did not include the undiscovered-rework loop. This report addresses that shortcoming by using a different project model that explicitly includes both the undiscovered-rework feedback loop and the rookie-professional up-to-speed delay. First, the initial system-dynamic model’s project plan gets modified to run with a realistic set of fine-tuned parameters and to produce a “best-case” project plan of acceptable scope, schedule, and cost. Then the best-case model’s “actual-to-date” staffing pattern becomes the “planned-value-to-date” staffing histogram for an “envelope” earned-value model. The envelope model sets its parameters to the best-case model and then uses system pressures derived from earned-value metrics to “work the plan” two ways: When everything goes according to plan, the envelope model correctly maintains the planned staff and scope to complete the project on time. When extra, unforeseen work is needed, the envelope model detects the need for additional staff or reduced scope and correctly adjusts the project to complete the project on time. Conclusion: The “envelope” model’s earned-value metrics prove completely adequate to manage the project successfully.