For our predictive project, we have identified project tasks and dependencies, sequenced them and assigned resources, determined the critical path, and mitigated initial risks. We began driving tasks forward, tracking progress, collecting data on task completion, and urging resources to finalize them according to the schedule. The project is important, so we keep pushing; however, more and more tasks are being delayed regardless the buffers incorporated in the task estimations. Delays accumulate and cannot be easily recovered. We add resources and the issues grow. Now, let us ask some initial questions that will guide us towards today’s topic.
• What happens if we push the beginning of the chain? Does it move in the direction we want?
• Why should we ask for “Estimate to Complete” (ETC) instead of “% Complete”?
• Why is “Almost Ready” misleading in task status?
• What is the disadvantage of “Critical Path” definition and calculation?
• Is there a way to improve project planning and control ensuring its completion on time?
Although the questions above involve common sense, they also highlight deeper project management challenges that are often overlooked in practice. ETC provides a forward-looking measure of the remaining effort needed to finish a project, while % complete only shows what has been done. A task that is 90% complete may still require a significant amount of work, making ETC more useful for planning and risk assessment. “Almost ready” is vague and can give a false sense of confidence. A task might appear nearly finished based on effort spent, but it may still require key dependencies, testing, or approvals. The Critical Path method focuses only on the longest sequence of dependent tasks, which can ignore hidden risks, resource bottlenecks, or external constraints. It also assumes fixed durations and does not adapt well to changes in execution speed or unforeseen issues.
Let’s examine these questions from the perspective of Critical Chain Project Management (CCPM). Although its foundational principles were incorporated into PMBOK as early as 1996, CCPM remains underutilized in modern project management. The methodology is rooted in the Theory of Constraints (TOC), developed by Eliyahu M. Goldratt, a management philosophy focused on identifying and addressing bottlenecks or constraints that limit system performance. His book “The Goal”, originally published in 1984, remains one of the most influential works in business management. Building on this concept within project management, he published “Critical Chain” book in 1997, where he expanded his ideas and formally introduced CCPM, which emphasizes the importance of managing project execution efficiently rather than forcing progress in an unstructured manner. Lets look at its principles:
• Critical Chain Identification: Unlike traditional methods that emphasize task order, CCPM prioritizes resource availability and dependencies, identifying and securing bottleneck resources.
• Buffer Management: Buffers protect the project schedule from uncertainties and delays by absorbing variability and preventing disruptions rather than forcing tasks forward artificially. Different types of buffers – project buffers, feeding buffers, and resource buffers – help maintain stability.
• Eliminating Waste: CCPM reduces inefficiencies caused by multitasking (favoring single-task execution), Parkinson’s Law (work expanding to fill available time), and student syndrome (delaying work until the last moment). It focuses on minimizing work in progress (WIP), controlling the number of open tasks, and minimizing handovers.
• Flexible Scheduling: Resources are leveled, and start times are dynamically adjusted to optimize workflow and avoid premature starts. Rather than pushing tasks forward before resources are ready, CCPM ensures work begins at the optimal time for a steady flow. Starting tasks as late as possible (ALAP), though counterintuitive, reduces lead time, minimizes unnecessary resource allocation, and helps focus on critical tasks while aligning with buffer consumption strategies. And most importantly, we now have the ability to recover from delays!
• Continuous Monitoring: Instead of tracking individual task performance, CCPM assesses buffer consumption to evaluate project health and progress.
In terms of metrics supporting decision making, I find Fever Charts extremely useful. They are a key visual tool used to track project progress and buffer consumption. They help project managers assess whether a project is on track or at risk of delay, and enable manager to take corrective action before issues escalate. Visuals provide a clear, real-time view of project health. Optimized buffer management helps prevent unnecessary delays by identifying risks early. This simple chart consists of horizontal axis representing project completion percentage and vertical axis representing buffer consumption – how much of the allocated buffer has been used, with three color zones:
• Green zone: The project is progressing well, with minimal buffer usage. No action is needed.
• Yellow zone : Some buffer is being consumed, indicating potential risks. Action plan is required.
• Red zone: Excessive buffer consumption, signaling urgent corrective action is needed. It prompts to act now.
It is worth mentioning that CCPM project management expertise and specialized software play a crucial role in the successful implementation of Critical Chain Project Management and buffer management. These tools assist in identifying constraints, managing buffers dynamically, and ensuring that resources are optimized throughout the project lifecycle. They also provide real-time visibility into project health, allowing teams to adjust strategies and mitigate risks.
Is CCPM a universal solution? No, CCPM is not a panacea for all projects. While it is highly effective for predictive projects, those with defined scopes, fixed deadlines, and clear dependencies, it has limitations in adaptive, evolving environments, where requirements change frequently or when probabilistic solution is required.
How can CCPM be enhanced? To maximize its effectiveness, CCPM is often combined with other methodologies: Lean, that helps eliminate waste and improve efficiency by reducing non-value-added activities, ensuring that resources focus on essential tasks as well as Agile and SAFe, which are essential for non-predictive projects, where flexibility, iterative cycles, and stakeholder feedback drive success. CCPM alone does not accommodate evolving requirements, but integrating Agile or SAFe allows teams to adjust workflows dynamically while maintaining resource efficiency.
On the other hand, for a probabilistic solutions, a cognitive approach, like CPMAITM is essential. For more details regarding CCPM and implementation, feel free to contact me.
– Greg