Stage-gate

Stage-gate commonly refers to a structured process for managing work through a series of defined stages, with a formal review or decision point, called a gate, between stages. At each gate, stakeholders assess whether the work is ready to proceed, needs rework, should be paused, or should be stopped.

In manufacturing and regulated operations, stage-gate is often used for product development, process changes, capital projects, validation-related activities, and implementation programs. The term describes the governance method around progression and approval, not the detailed execution of each task inside a stage.

What it includes

• Predefined stages such as concept, feasibility, development, testing, launch, or deployment

• Entry and exit criteria for each stage

• Gate reviews based on evidence, status, risk, cost, quality, and readiness

• Named decision-makers or review groups responsible for approving progression

• Documentation, records, and traceable decisions where required by internal controls or regulated workflows

What it does not mean

Stage-gate does not by itself define a specific quality standard, validation protocol, or regulatory requirement. It also is not the same as a production routing, shop floor operation sequence, or workflow engine, although software systems may support stage-gate reviews with approvals, status controls, and evidence collection.

Operational meaning

In practice, a stage-gate model appears as a controlled progression of work items or projects. For example, an engineering change may move through proposal, impact assessment, approval, implementation, and verification, with a gate at each transition. In digital systems, gates may be represented by workflow states, approval tasks, required attachments, e-signatures, or role-based release controls.

Common confusion

Stage-gate is often confused with a milestone plan. A milestone is a notable event or target date, while a gate is a decision point tied to explicit review criteria. It is also sometimes confused with phase-gate. In many organizations, phase-gate and stage-gate are used interchangeably, though local terminology may differ.

Another common confusion is with manufacturing process stages. A stage-gate framework governs whether work can advance; it does not necessarily describe physical production steps such as machining, assembly, inspection, or packaging.