Product Development Process and Lifecycle
Domain 1 tests whether you can place a development project on a structured lifecycle, choose an appropriate process model, and defend gate and design-freeze decisions with evidence rather than enthusiasm.
Two lifecycles that are often confused
- The product development process (PDP) is the project path: discovery, scoping, business case, development, verification and validation, launch, post-launch review. Stage-Gate overlays deliverable-based gates with go/kill/hold/recycle decisions.
- The product life cycle (PLC) is the market path: introduction, growth, maturity, decline. It drives pricing, variant proliferation and end-of-life planning, not gate reviews.
- The V-model decomposes requirements on the left and verifies them on the right. Agile and hybrid models run sprints inside a gated envelope; they do not remove configuration control.
Control points
A gate is an evidence-based AND decision, not a schedule milestone. Criteria normally cover market, technical, financial and risk dimensions. Design freeze should follow demonstrated maturity, and any later change must go through an engineering change note (ECN) with impact assessment. Concurrent engineering overlaps activities to shorten lead time, but the cost of a change rises sharply after tooling release.
Worked example
A gate review forecasts 40,000 units in year one, price €22, COGS €14, so gross margin is €8 per unit and €320,000 in year one. Tooling is €180,000, giving payback in 0.56 years. Financially the case passes. However, reliability testing shows 2 failures in 12 units and MTBF below target. The correct decision is conditional go: release only long-lead tooling, hold production tooling, and set a six-week corrective action with re-test. A failed technical criterion cannot be offset by a strong business case unless the risk is explicitly accepted by the accountable owner.
Traps that cost marks
- Treating the PLC as the development process, or a gate as a date.
- Freezing design before verification, then managing late changes informally.
- Using a single financial metric and ignoring reliability, regulatory or lifecycle cost.
- Saying Stage-Gate is bureaucratic without discussing tailoring for uncertainty.