Development methodologies
- 2. LEARNING INTENTIONS • To know the difference between Iterative and Agile approaches to development • Learn about the advantages and disadvantages of each approach
- 3. ITERATIVE METHODOLOGIES • Iterative (repetitive) process is the constant review and improvement until it is as refined as it can be. • The most common method of this is the waterfall method where the programmer will continue to go over and refine steps again.
- 4. THE WATERFALL METHOD Implementation Analysis Design Testing Evaluation Maintenance iteratio n & feedb a ck D ocum entation
- 5. THE WATERFALL METHOD • Sometimes looking over a stage that is carried out may provide evidence that the previous phase requires further improvement. • This could be described as iterative feedback. • For example testing results may show that code (or even design) needs improved. Issues in the design phase may even be a consequence of lack of clarity in the software specification produced during analysis.
- 6. PROBLEMS WITH ITERATIVE DEVELOPMENT • The problem with traditional iterative methodologies such as the Waterfall model was that some applications took so long to build that requirements changed before the system was complete, often resulting in software which was no longer fit for purpose. • In February 1991, 17 prominent software developers met in Utah to discuss 'lightweight' development methods. The outcome of this was the Manifesto for Agile Software Development. • Compared to the waterfall model, Agile is a more flexible and less formal approach where the end-users/clients are much more involved in what is built by providing feedback throughout the development process.
- 7. AGILE SPRINTS • Agile development is broken into lots of short stages, called sprints. At the start of each sprint, the development team agree on what features still to be implemented from the product specification (the backlog) will be the focus for the current sprint. • Each sprint could be described as a 'micro waterfall' because it still involves analysis, specification, design, implementation, testing and maintenance. • In a sprint, team members aim to achieve goals within set timeframes. A sprint usually lasts from 1 to 3 weeks depending on the development company.
- 8. AGILE SPRINTS • Have regular team meetings (several a week or even daily) to provide an opportunity for team members to discuss the previous day's work, what they plan to work on in the next day or two and any issues which are blocking their progress. • Every sprint iteration generally produces a working and tested software increment (new version) which is shipped to users who evaluate it and provide feedback. • Agile methodology is described as iterative and incremental.
- 10. ADVANTAGES OF AGILE METHODOLOGY • Customer involvement and collaboration: Better decisions can be made about the product development where the customer is involved throughout the development process. This is more likely to result in a product that meets all the customer's needs. • Less extensive documentation: While documentation is still an important aspect of Agile development in defining sprint scope, designing new components and testing, the emphasis is on coding to complete the current iteration of the software. • Responsive to change: It is relatively easy to accommodate changing requirements from the customer throughout the development process.
- 11. ADVANTAGES OF AGILE METHODOLOGY • Measuring progress: Regularly delivering functional software increments to the customer is the ultimate factor that measures progress and assures them of the progress that is being made. This also results in customer satisfaction. • Motivated and effective development team: Skilled and motivated team members who have decision-making power, take ownership, communicate regularly with other team members, and share ideas and techniques to deliver quality products. • Less emphasis on initial specification and contract negotiation: Fully defining every detail of a software specification at the outset is actually quite a difficult task as the clients may struggle to fully visualise and verbalise what they want out of their software, particularly in a completely new project where no software existed before.
- 12. DISADVANTAGES OF AGILE METHODOLOGIES • Scope Creep: Lack of a clearly defined specification and final outcome at the outset makes project management difficult since the processes and their scheduling are less predictable. Clients can keep changing the project scope and if the project manager is not experienced, the project can keep growing, come in late and over budget. • Speed over Quality: In Agile, rapid production is more important than product quality. Time pressures in each sprint may lead to team members 'cutting corners' in design processes and coding. This might result in inefficient code and a less polished product. • Scalability: Agile is not ideal for large complex systems but is better suited to small & medium sized projects.