The principal responsibility of software project managers is to manage the project so that the software is delivered on time and within the planned budget for the project. They supervise the work of software engineers and monitor how well the software development is progressing. The standard approach to project management is plan-driven. A plan-based approach really requires a manager to have a stable view of everything that has to be developed and the development processes. However, it does not work well with agile methods where the requirements are developed incrementally; where the software is delivered in short, rapid increments; and where changes to the requirements and the software are the norm. Like every other professional software development process, agile development has to be managed so that the best use is made of the time and resources available to the team. This requires a different approach to project management, which is adapted to incremental development and the particular strengths of agile methods.
The Scrum approach (Schwaber, 2004; Schwaber and Beedle, 2001) is a general agile method but its focus is on managing iterative development rather than specific technical approaches to agile software engineering. Figure 3.8 is a diagram of the Scrum management process. Scrum does not prescribe the use of programming practices such as pair programming and test-first development. It can therefore be used with more technical agile approaches, such as XP, to provide a management framework for the project.
There are three phases in Scrum. The first is an outline planning phase where you establish the general objectives for the project and design the software architecture.
This is followed by a series of sprint cycles, where each cycle develops an increment of the system. Finally, the project closure phase wraps up the project, completes required documentation such as system help frames and user manuals, and assesses the lessons learned from the project.
The innovative feature of Scrum is its central phase, namely the sprint cycles.
A Scrum sprint is a planning unit in which the work to be done is assessed, features are selected for development, and the software is implemented. At the end of a sprint, the completed functionality is delivered to stakeholders. Key characteristics of this process are as follows:
1. Sprints are fixed length, normally 2–4 weeks. They correspond to the development of a release of the system in XP.
2. The starting point for planning is the product backlog, which is the list of work to be done on the project. During the assessment phase of the sprint, this is reviewed, and priorities and risks are assigned. The customer is closely involved in this process and can introduce new requirements or tasks at the beginning of each sprint.
3. The selection phase involves all of the project team who work with the customer to select the features and functionality to be developed during the sprint.
4. Once these are agreed, the team organizes themselves to develop the software. Short daily meetings involving all team members are held to review progress and if necessary, reprioritize work. During this stage the team is isolated from the customer and the organization, with all communications channelled through the so-called ‘Scrum master’. The role of the Scrum master is to protect the development team from external distractions. The way in which the work is done depends on the problem and the team. Unlike XP, Scrum does not make specific suggestions on how to write requirements, test-first development, etc. However, these XP practices can be used if the team thinks they are appropriate.
5. At the end of the sprint, the work done is reviewed and presented to stakeholders.
The next sprint cycle then begins.
The idea behind Scrum is that the whole team should be empowered to make decisions so the term ‘project manager’, has been deliberately avoided. Rather, the ‘Scrum master’ is a facilitator who arranges daily meetings, tracks the backlog of work to be done, records decisions, measures progress against the backlog, and communicates with customers and management outside of the team.
The whole team attends the daily meetings, which are sometimes ‘stand-up’ meetings to keep them short and focused. During the meeting, all team members share information, describe their progress since the last meeting, problems that have arisen, and what is planned for the following day. This means that everyone on the team knows what is going on and, if problems arise, can re-plan short-term work to cope with them. Everyone participates in this short-term planning—there is no top down direction from the Scrum master.
ADVANTAGES OF AGILE SOFTWARE DEVELOPMENT:
1. The product is broken down into a set of manageable and understandable chunks.
2. Unstable requirements do not hold up progress.
3. The whole team has visibility of everything and consequently team communication is improved.
4. Customers see on-time delivery of increments and gain feedback on how the product works.
5. Trust between customers and developers is established and a positive culture is created in which everyone expects the project to succeed.
