Waterfall and Scrum

Scrum (right), an Agile software development methodology, has become more popular than the traditional Waterfall (left) methodology in recent years, especially for teams that must deliver frequent incremental releases through cloud services or mobile application stores.

Waterfall is characterized by discrete phases that can run for months and gate the commencement of subsequent phases. For example, development work might not begin until design specifications have been reviewed and finalized. Parts of the cycle are usually repeated for milestones such as alphas, betas, and a final release. Waterfall gives teams a relatively long time window for focusing on and solving the problems of each phase, but members can be underutilized while waiting for others to complete work. Furthermore, the process is disrupted when customer or design team requirements change, leading to difficult management decisions and slipped schedules, which can leave current customers with an aging previous version of the product.