Intro to Project Management: Project Life Cycle - Predictive Waterfall vs. Adaptive, Agile Life Cycles

Predictive (Waterfall) vs Adaptive (Agile) Life Cycles

What This Is

Predictive (Waterfall) and Adaptive (Agile) life cycles are two fundamental approaches to managing projects. Predictive life cycles follow a linear, sequential process, while Adaptive life cycles are iterative and flexible. Understanding the differences between these two approaches is crucial for successful project delivery. For instance, building a bridge requires a predictable, phased approach, whereas launching a software product may benefit from an adaptive, iterative approach.

Key Terms & Formulas

• Predictive Life Cycle: A linear, sequential approach to project management, where each phase is completed before moving on to the next.
• Adaptive Life Cycle: An iterative and flexible approach to project management, where requirements and scope are refined throughout the project.
• Triple Constraint: Scope, Time, Cost – changes to one affect the others.
• EV = % complete × BAC (Earned Value = percent complete times Budget at Completion)
• CPI = EV ÷ AC (Cost Performance Index = Earned Value ÷ Actual Cost)
• SPI = EV ÷ PV (Schedule Performance Index = Earned Value ÷ Planned Value)
• Earned Value (EV): The value of work completed, calculated as a percentage of the Budget at Completion (BAC).
• Actual Cost (AC): The total cost incurred to complete the work.
• Planned Value (PV): The budgeted cost of work scheduled to be completed.
• Schedule Performance Index (SPI): A measure of how well the project is progressing in terms of time.
• Cost Performance Index (CPI): A measure of how well the project is progressing in terms of cost.

Step-by-Step / Process Flow

1. Identify the project life cycle: Determine whether the project requires a predictive or adaptive approach based on its characteristics, such as complexity, uncertainty, and stakeholder expectations.
2. Develop a project plan: Create a detailed project plan, including a work breakdown structure (WBS), schedule, budget, and resource allocation, for predictive projects.
3. Establish a project framework: Set up a project framework, including a product backlog, sprint planning, and daily stand-ups, for adaptive projects.
4. Monitor and control: Regularly track and report on project progress, identifying and addressing deviations from the plan.
5. Adjust the approach: Be prepared to adjust the project approach as needed, based on changes in requirements, scope, or stakeholder expectations.

Common Mistakes

• Mistake: Assuming a predictive life cycle is always the best approach.
• Correction: Consider the project's characteristics and stakeholder expectations before selecting a life cycle approach.
• Mistake: Failing to regularly track and report on project progress.
• Correction: Establish a monitoring and control process to identify and address deviations from the plan.
• Mistake: Not being prepared to adjust the project approach as needed.
• Correction: Be flexible and adapt the project approach to changes in requirements, scope, or stakeholder expectations.

Exam Tips

• Distinguish between predictive and adaptive life cycles: Be able to explain the key differences between these two approaches and when to use each.
• Understand the triple constraint: Recognize how changes to one aspect of the triple constraint (scope, time, cost) affect the others.
• Calculate earned value metrics: Be able to calculate EV, AC, PV, SPI, and CPI, and understand their implications for project performance.

Quick Practice Questions

1. If the CPI is 0.8, is the project under or over budget? Answer: Under budget. Explanation: A CPI of 0.8 indicates that the project is earning value at a rate that is 80% of the actual cost incurred.
2. If the EV is $100,000 and the BAC is $200,000, what is the percent complete? Answer: 50%. Explanation: EV = % complete × BAC, so 100,000 = 0.5 × 200,000.
3. If the SPI is 1.2, is the project ahead or behind schedule? Answer: Ahead of schedule. Explanation: An SPI of 1.2 indicates that the project is earning value at a rate that is 20% faster than planned.

Last-Minute Cram Sheet

• Predictive life cycles follow a linear, sequential process.
• Adaptive life cycles are iterative and flexible.
• The triple constraint includes scope, time, and cost.
• EV = % complete × BAC.
• CPI = EV ÷ AC.
• SPI = EV ÷ PV.
• Earned value metrics are used to measure project performance.
• A CPI of 0.8 indicates a project is under budget.
• A SPI of 1.2 indicates a project is ahead of schedule. Decomposition breaks down work, not activities – it creates the WBS, not the activity list. Earned value metrics are not the same as actual cost or planned value. A predictive life cycle is not always the best approach.