Introduction to the "Scrum" Software Development Process

"Scrum" is not an acronym, and instead the name comes from a type of rare, in-game meeting used by soccer team members to do medium-term planning. Instead of dividing a big project into separately-developed pieces (which must be integrated at the end), or splitting the project temporally into a series of stages done different groups (where there is a handoff of responsibility from design, to implementation, to testing, etc), the idea behind Scrum is to create a stable team that handles the entire project through a series of atomic steps called "sprints". The endpoint after each sprint should be a "Potentially Shippable Increment" (PSI), which is a working, stable, fully-documented piece of code that implements a subset of the features required in the complete project.

For example, suppose the overall project goal is to build a house.

• You could organize the work by splitting the project into separate tasks completed by different individuals: (1) someone builds the walls in his factory, (2)  another person builds the roof in his factory, etc. Then late in the process all of these sub-assemblies are brought to the site for integration and testing -- where someone has to make them fit together correctly, making last-minute modifications as necessary. (BTW, this is basically how commercial airplanes are built today. Early in the process, large sections of the plane are given to different sub-contractors to design and build -- sometimes in other countries.)
• You could organize the work into sequential stages involving different types of specialization, such as: (1) building the wooden framing, (2) adding the plumbing, (3) adding electrical wiring, (4) covering the walls with drywall, (5) painting the walls, (6) installing the flooring, etc. In this case, there is a "hand-off" of responsibility between stages, so the framer never hears that one of his decisions made it needlessly difficult to install the plumbing or get the drywall to lay flat. (BTW, this is basically how large-scale developers build subdivisions, with different tradesmen visiting each house under construction in the right order.)
• You could organize the work the way I've seen it in the Middle East, where extended families build homes incrementally with their savings, because banks do not loan enough money to complete the entire house at one time.  Thus, the family starts by digging a hole in the ground and building concrete walls and floor inside to form the basement foundation. Once this underground space is covered by the floor of the future house, the family can move in and live there until they have saved up enough money to build a livable section of first floor, and so on.  THIS is basically how Scrum would handle the work!