A comparison of FDD and Scrum

FDD and Scrum are two examples of agile development methodologies. Agile development tries to avoid the main weakness of "waterfall" by doing iterative development. Each iteration is meant to be short (1-2 weeks) and includes all of the following steps.

• Gathering user requirements
• Design and documentation
• Development
• Testing
• Deployment

This guarantees that design errors are discovered at early stages of development. I've had experience on working on projects using both methodologies and it was interesting to compare the salient features of both approaches.  Before the comparison, a short overview of each practice is given.

Feature Driven Development
Feature Driven Development, FDD  is an agile software development methodology by Jeff De Luca and Peter Coad.  It has more formal requirements and steps than Scrum from a development perspective.

 

FDD consists of five high level activities:

• Develop an overall domain mode
• FDD advocates light modelling up front to understand the shape and scope of the application.
• Build a list of features
Team builds a feature list.  Each feature represents 1-10 days worth of effort.  
A feature is a small piece of client-valued function expressed in the form: <action> <result> <object> i.e. Calculate the total of a sale
• Plan by feature
• Features are then assigned to iterative release cycles.
• Developers are also assigned to own particular classes identified in the domain model by a chief programmer.
• Design By Feature (DBF)
• Feature teams are assigned to a set of features and proceed to the design in detail i.e. sequence diagrams 
• Build By Feature (BBF)
• Those teams then carry out the code development and testing of those features.
• When chief programmer is satisfied then completed features are promoted to the main build.

FDD utilizes chief programmer, inspections, and class ownership. The chief programmers function as team leaders, mentors, and reviewers. While the term chief programmer may suggest micro-management and control, FDD teams stress the collaboration and knowledge sharing roles.


Progress and can be tracked and reported with accuracy by assigning a percentage weighting to each step in a DBF/BBF iteration The chief programmers indicate when each step has been completed for each feature they're developing. This enables a view on how much of a particular feature has been completed.  The cycle repeats itself either by refinement of the original domain model and subsequent activities or until all the features in the list have been built.

Scrum

Scrum is an iterative, incremental framework for project management often seen in agile software development, a type of software engineering. Essentially Scrum boils down to the following points (from Scrum Alliance):