Fourstage

Fourstage, sometimes written as four-stage, is a general descriptor used across disciplines to denote a process or system divided into four sequential phases. Because it is a versatile pattern rather than a fixed framework, the specific meaning of each stage depends on the domain, organization, and objectives. The concept is commonly employed to improve planning, tracking, and evaluation by making progression explicit.

Common four-stage frameworks include the following domain examples:

- Project management: initiation, planning, execution, closure.

- Product development: ideation, design/development, testing/validation, launch.

- Software or data engineering: ingestion, transformation, storage, retrieval.

- Education and training: introduction, practice, assessment, feedback.

Variations exist in labeling and emphasis; some models use initiation, development, deployment, and refinement, while others call stages planning, execution, validation, and sustainment. The four-stage pattern is often paired with feedback loops or gates to ensure quality at transitions. Because the term describes a generic progression rather than a unique method, fourstage models are frequently tailored to organizational needs, project scopes, and performance metrics.

See also: stage-gate processes, phased lifecycle models, and other structured approaches to project or product development. As a flexible pattern, fourstage serves as a framework for organizing activities, aligning teams, and monitoring progress across diverse fields.