Catalog
method#Delivery#Governance#Product#Software Engineering

Waterfall Model

Sequential development model with defined phases and formal handovers, suited for projects with stable requirements.

The Waterfall model is a sequential software development approach with distinct phases such as requirements analysis, design, implementation, testing, and maintenance.
Established
Medium

Classification

  • Medium
  • Organizational
  • Organizational
  • Intermediate

Technical context

Project management tools (e.g. MS Project)Documentation platforms (e.g. Confluence)Testing and QA tooling

Principles & goals

Sequential phases with clear handoversComprehensive documentation and planning disciplineFormal reviews and approvals before progression
Build
Enterprise, Domain, Team

Use cases & scenarios

Compromises

  • Lack of user involvement during development
  • Late integration causes costly rework
  • Rigid contracts lead to conflicts on changes
  • Validate detailed requirements early with stakeholders
  • Define clear acceptance and review gates
  • Maintain and version documentation continuously

I/O & resources

  • Complete requirements specification
  • Project plan with milestones
  • Fixed budget and resources
  • Acceptable final product
  • Complete development and test documentation
  • Acceptance records and release approvals

Description

The Waterfall model is a sequential software development approach with distinct phases such as requirements analysis, design, implementation, testing, and maintenance. It emphasizes thorough upfront planning, formal handovers and defined roles, making projects with stable requirements predictable. However, it offers limited flexibility for late changes.

✔

  • Predictability of time and cost for stable requirements
  • Clear responsibilities and intermediate deliverables
  • Suitable for regulatory and contractual requirements

✖

  • Low flexibility for late requirement changes
  • Risk of late defect discovery in the project cycle
  • High upfront documentation effort

  • Schedule adherence

    Measures whether milestones are met according to plan.

  • Number and severity of reworks

    Captures effort and cost for fixes after integration.

  • Documentation completeness

    Rates completeness of specifications, tests and handovers.

Control software for industrial plant

Delivery of a complete control module according to predefined specifications with formal acceptance by the operator.

Government IT procurement

Project with fixed requirements and contractual scope where Waterfall is used to satisfy compliance.

Migration of a legacy subsystem

Planned, phased migration with extensive documentation and final integration testing.

1

Collect and document full project scope and requirements

2

Create comprehensive project plan with milestones and roles

3

Execute phase-wise, test and perform formal acceptances

⚠️ Technical debt & bottlenecks

  • Architectural choices that hinder later changes
  • Lack of automated integration tests
  • Incomplete infrastructure documentation
late-integrationrequirements-freezelong-feedback-loops
  • Using it for highly uncertain or exploratory projects
  • Applying it without formal approvals in regulated projects
  • Relying on documentation instead of actual testing
  • Overestimating requirement stability
  • Underestimating rework costs
  • Lack of end-user involvement until acceptance
Requirements analysis and specificationFormal project and phase managementVerification and validation testing
Stable requirementsRegulatory traceabilityPredefined interfaces
  • • Fixed contractual scope
  • • Limited user availability for iterations
  • • Sequential phases with gate reviews