Critical chain and the ProChain System

This article covers two related topics:

Critical chain, a method for scheduling projects; and
The ProChain System, a methodology that enables project stakeholders to use those schedules to achieve dramatic improvements in speed, on-time performance, and overall quality of life.

Fusion Online—along with Fusion Pipeline for multi-project and program-level scheduling—fully supports both critical chain and the ProChain System, helping you realize their full benefits.

Introduction

Project workers face a difficult challenge: they must create schedules that are guaranteed to be wrong. Individual task deadlines can only be met if they’re padded with safety time—time intended to absorb delays from resource bottlenecks, other projects, meetings, and fumbled handoffs. People know that if that safety time isn’t fully used, they'll be held accountable to shorter durations next time. That means early delivery is rare.

When those padded task deadlines are rolled up into a project schedule, team members are left with two choices: commit to an unrealistic timeline and miss their commitments, or commit to a significant amount of safety time, which at best will be used up.

The ProChain System changes that paradigm. Instead of working to deadlines, people work to priorities. Everyone knows which task is most important and focuses on it until it’s done and handed off. Prioritize. Focus. Finish. Making that work requires critical chain schedules—along with the ProChain System to build and execute them effectively.

Critical chain schedules

Critical chain scheduling is similar to standard critical path scheduling in that it starts with a dependency network. That network includes tasks with duration estimates, links between tasks (the dependencies), and other supporting data such as calendars and resource assignments.

Critical path scheduling is straightforward: schedule everything as soon as possible, then identify the longest path through the network. The tasks along that path make up the critical path.

ProChain’s critical chain scheduler goes farther:

Task duration ranges—including both an aggressive (or focus) duration and a conservative (or low-risk) duration—replace the single duration used in traditional critical path.
It aggregates uncertainty from the task duration ranges to create a project buffer or landing zone. The buffer protects the project completion commitment by making overall uncertainty explicit and manageable.
It uses the focus durations to construct a schedule for all the tasks.
It calculates the critical chain—the subset of tasks on which people really need to focus to complete the project as quickly as possible. The critical chain is analogous to the critical path, but it also accounts for limited resources, to the extent they are modeled.
Non-critical tasks may be scheduled later than ASAP, recognizing that not everything available to work on now should be worked on now.

The ProChain scheduler can also schedule multiple projects, and even delay lower-priority projects when capacity is constrained. For more information, see the Fusion Pipeline User’s Guide and Help.

The ProChain System

Building a network

Part of the ProChain System is a process called Network Building, which enables your team to create a schedule with clear, shared priorities. This process takes effort—but by using Fusion Online alongside the ProChain System, you will gain the discipline, simplicity, and priorities you need to deliver your projects effectively.

Working to the schedule

Projects complete faster when all team members run a relay race: each person works as quickly as possible on their highest priority task, and passes it on. Prioritize. Focus. Finish.

Teams are encouraged to take extra measures to help each other focus on high-priority tasks. For example, they can provide help, avoid interruptions, and excuse key workers from meetings when possible. Remember: a one-day delay on a critical chain task translates directly to a one-day delay of the project.

The ProChain System recommends a cycle called the Progress Loop for keeping schedules accurate and projects moving forward. It’s designed to help teams deliver projects rapidly and reliably.

Here’s how the cycle works:

Team Alignment begins with shared ownership of the schedule, building credibility across your team even in the face of uncertainty
The team shares priorities based on the current schedule.
That allows team members to make progress on top-priority tasks—minimizing multitasking and handing off quality work: Prioritize. Focus. Finish.
When tasks are completed—or at least once per week—team members update the tasks so the schedule remains an accurate picture of the work going forward. (Updating a task in Fusion Online takes only a few seconds.)
The Project Manager then analyzes the fever chart and the priority tasks to see how delays can be avoided and acceleration opportunities seized, while assigning work as appropriate.
Finally—and perhaps most importantly—the team meets weekly in a Progress Meeting, described below. The team should leave the meeting with a shared understanding of priorities and actions required to deliver the project rapidly and reliably.

This dynamic feedback loop allows an organization to respond quickly to problems—and even anticipate them—accelerating project completion dramatically. It stands in contrast to traditional deadline-driven systems, where reactions to problems tend to be localized and slow.

The Progress Meeting

The Progress Meeting is typically held weekly and includes about 8 to 12 core team members, including the Project Manager. The meeting has three main goals:

1. Understand status relative to commitments

Overall project status is tracked using the Fever Chart, which shows the rate of project buffer consumption compared to the rate of project completion.

Buffers are “consumed” when critical chain tasks take longer than their focus durations. Unsustainably high rates of buffer consumption show up in the red zone of the fever chart and indicate a threat to completing the project on time.

2. Make sure everyone is aligned on priorities

Before the meeting, the schedule is updated in Fusion Online to recalculate the critical chain.

During the Progress Meeting, the team analyzes the impact chain, which shows the current critical chain and almost-critical chain tasks (the "high priority" tasks). The goal is to ensure that the most important tasks for the coming week will receive the focus and support they need. For example, someone working on a high-priority task may be excused from non-essential meetings or responsibilities to help them stay focused and finish quickly.

3. Look for additional opportunities to accelerate the project

The impact chain isn’t just useful for identifying priority—it also helps surface opportunities to go faster. Teams should challenge how tasks are planned and executed, and stay proactive about finding ways to go even faster on the critical chain.

Summary

The ProChain System, powered by critical chain schedules, provides more than just a better way to plan—it enables teams to focus on priorities, respond to uncertainty, and keep momentum going. When priorities are clear and the team is aligned around them, execution becomes faster, smoother, and far more effective.

Keep the loop going. With consistent use, the system becomes not just a tool—but a culture shift that transforms the way your organization manages projects.