Project life cycles define the approach and sequence of project activities. They vary based on project complexity, risk, and customer needs. This article describes the characteristics of four project life cycles: predictive, iterative, incremental, and agile.

Predictive life cycles are designed to take advantage of high certainty around firm requirements, a stable team, and low risk. The project activities typically execute in a serial manner and require detailed plans to manage risk and cost. These projects aim to minimize change, and any potential changes are restricted. Predictive projects deliver business value at the end of the project, and any changes or disagreements with the requirements can result in unanticipated costs.

Iterative life cycles improve the product through successive prototypes or proofs of concept. Each new prototype yields new stakeholder feedback and team insights, which are incorporated by repeating one or more project activities in the next cycle. Iterative projects benefit when complexity is high, and the project incurs frequent changes or differing stakeholders’ views of the desired final product. These projects are optimized for learning rather than speed of delivery, and the delivery of business value occurs incrementally.

Incremental life cycles optimize work for delivering value to sponsors or customers more often than a single, final product. Teams plan initial deliverables before beginning their work, and they begin working on that first delivery as soon as possible. The degree of change and variation is less important than ensuring customers get value sooner than at the end of the project. Agile teams, as a key differentiator, deliver business value often. They may choose to deliver a minimum viable product (MVP) to a subset of customers, allowing adjustments to be made before further investments of time and money.

Agile life cycles work in iterations or based on a flow-based approach. In iteration-based agile, the team works on iterations to deliver completed features, while in flow-based agile, the team pulls features from the backlog based on its capacity to start work. Agile teams expect requirements to change, and incremental delivery uncovers hidden or misunderstood requirements.

In conclusion, project managers must choose the appropriate life cycle to meet the project objectives, taking into account the level of complexity, risk, and customer needs. Understanding the characteristics of each life cycle can help teams manage the project effectively and deliver business value.