When requirements are well understood and control matters, predictive delivery excels. Waterfall provides the sequence; PRINCE2 provides the governance.
Waterfall
Waterfall delivers in sequential phases — typically requirements → design → build → test → deploy → maintain — each largely completed before the next begins. It's easy to plan, budget and govern, and works well for fixed-scope, well-defined projects (construction, regulated change, infrastructure). Its weakness: change is expensive late, and value only arrives at the end.
PRINCE2 in a nutshell
PRINCE2 (PROjects IN Controlled Environments) is a widely used, tailorable method built on three things:
7 principles (always apply): continued business justification; learn from experience; defined roles & responsibilities; manage by stages; manage by exception; focus on products; tailor to suit the project.
7 themes (what you set up and maintain): Business Case, Organisation, Quality, Plans, Risk, Change, Progress.
7 processes (the flow): Starting Up, Directing, Initiating, Controlling a Stage, Managing Product Delivery, Managing a Stage Boundary, Closing a Project.
Key PRINCE2 ideas
- Business case first — the project must stay justified throughout, or it's stopped.
- Manage by stages — the project is broken into stages with go/no-go decisions at each boundary.
- Manage by exception — the PM works within agreed tolerances (time, cost, scope, risk, quality, benefit) and only escalates when a tolerance will be breached. This frees senior management from day-to-day detail.
- Product focus — define the products (deliverables) and their quality criteria up front.
Predictive vs adaptive — the trade-off
Predictive gives certainty, auditability and control but resists change. Adaptive (Agile) embraces change but is harder to fix-price. Choose by the nature of the work — and remember most organisations run a hybrid: PRINCE2 governance around agile delivery.
Put it to work
For a current project, write a one-line business case and identify your stages and tolerances — then decide whether predictive, agile or hybrid fits best.