GCSE Computer Science: Software Development Life Cycle Guide

Stages of development

Software is typically developed through stages: analysis (understanding requirements), design, implementation (writing the code), testing, and maintenance (fixing issues and making updates after release).

The Waterfall method

The Waterfall method completes each stage fully before moving to the next, in a strict linear sequence — straightforward to manage, but inflexible if requirements change partway through.

Agile development

Agile development breaks a project into small stages ("sprints"), building, testing and reviewing working software repeatedly and adapting to feedback and changing requirements throughout the project.

Testing

Testing checks a program works correctly, including using both valid data (expected input) and invalid or boundary data (extreme or incorrect input) to check the program handles all cases appropriately.

Common mistakes

• Assuming Waterfall and Agile are interchangeable — they suit different types of project.
• Forgetting maintenance is an ongoing stage after a program is released, not a one-off step.
• Testing only with expected, valid data and ignoring boundary or invalid data.