Predictive, Plan-Based Methodologies
Predictive approaches plan scope, schedule, and cost in detail up front and manage change formally. This chapter introduces when to use them and the core scheduling and cost tools they rely on.
When predictive fits
Predictive, plan-based life cycles suit projects with well-understood, stable requirements that can be defined early. Detailed planning happens before execution, and change is handled through a formal change control process to protect the baselines.
Scheduling and the critical path
Activities are sequenced into a network diagram. The critical path is the longest path through the network and sets the shortest possible project duration; its activities have zero float, so any delay there delays the project.
Cost estimating and earned value
Estimates grow more accurate over time, from rough order of magnitude to definitive. Earned value management compares planned value, earned value, and actual cost; indices such as CPI and SPI reveal whether the project is over or under budget and ahead of or behind schedule.