The waterfall software development life cycle is a methodology that divides the project into phases,

and the project manager focuses on control of time, cost, and scope. The waterfall model is a linear

and sequential approach that follows a predefined set of steps from the initiation to the closure of

the project. The waterfall model assumes that the requirements, scope, and design of the project are

clear and stable, and that each phase can be completed before moving to the next one. The waterfall

model helps to ensure that the project deliverables meet the quality standards and specifications,

and that the project is completed within the budget and schedule12. The spiral software

development life cycle is a methodology that combines the iterative and incremental approach with

the risk management and prototyping techniques. The spiral model is a cyclical and evolutionary

approach that follows a series of loops or iterations from the planning to the deployment of the

project. The spiral model assumes that the requirements, scope, and design of the project are

dynamic and complex, and that each iteration can be refined and improved based on the feedback

and learning from the previous ones. The spiral model helps to identify and mitigate the risks and

uncertainties of the project, and to deliver a functional and adaptable product13. The agile software

development life cycle is a methodology that emphasizes the collaboration, communication, and

flexibility among the project stakeholders. The agile model is an adaptive and iterative approach that

follows a series of short and frequent cycles or sprints from the conception to the delivery of the

project. The agile model assumes that the requirements, scope, and design of the project are

emergent and changing, and that each sprint can deliver a working and valuable product

increment. The agile model helps to respond to the changes and feedback of the project, and to

maximize the customer satisfaction and value14. The incremental software development life cycle is

a methodology that breaks down the project into smaller and manageable chunks or modules. The

incremental model is a progressive and modular approach that follows a series of steps from the

analysis to the implementation of each module of the project. The incremental model assumes that

the requirements, scope, and design of the project are partially known and defined, and that each

module can be developed and delivered independently. The incremental model helps to reduce the

complexity and risk of the project, and to provide a gradual and continuous delivery of the

product15. Reference:

CBAP® Handbook

Waterfall Model - iiba.org

Spiral Model - iiba.org

Agile Model - iiba.org

Incremental Model - iiba.org