Critical Chain Solar Project Management: Page 3 of 3

Implementing Critical Chain

The following steps in critical chain project management illustrate how to apply these procedures to solar projects.

Step 1: Plan and estimate. Start with a project plan or work breakdown structure that identifies all the tasks necessary for project completion. Work through the tasks backward, starting from a completion date, with each task starting as late as possible. Assign two durations to each task: The first date is your best guess at the duration, with a 50% probability of completion; the second date is your conservative estimate of the duration, with a 90% probability of completion.

Step 2: Allocate resources. Assign resources to each task by deciding who will do what. To balance the demand for resources with the supply, employ resource leveling across the plan by analyzing previous projects to understand the production capabilities of installation technicians, designers, engineers, administrative staff and other project actors. Develop a project schedule using the most aggressively short durations possible. The critical chain improves on the critical path method because the critical chain is the longest sequence of tasks, with resource constraints applied, leading from the beginning to the end of the project. You can break out other tasks into the feeding paths leading into that critical chain. The difference between the 90% and 50% durations you determined earlier becomes the buffer at the end of the project.

Step 3: Start the relay race. Critical chain project execution is like a relay race. As the runner with the baton approaches the person responsible for the next leg of the race, that next person takes off and both runners run side by side until they reach the handoff point. Similarly, the goal of critical chain project management is to eliminate waiting times between tasks by allowing the next person in the critical chain to see when the previous task is coming to completion and his or her task is about to start. Balancing the workload of resources is where the art and science of resource leveling comes in. Project execution is also a potential source of work culture conflicts. In project environments with many interruptions, resources are often under pressure to multitask. Critical chain discourages multitasking or any delay to the start of a task.

Step 4: Monitor progress. In a critical chain, individual tasks will always vary in duration from the 50% estimate. Pressuring resources to complete every task on time is an exercise in futility. There is no need for the perfect to be the enemy of the good. Instead, project managers and project actors should monitor the buffers agreed upon during the planning stage. As long as the remaining buffers are adequate, everyone is doing a good enough job of keeping the project on schedule. Often, this “good enough” aspect of resource-based critical chain project management is the most difficult mental hurdle for project managers more familiar with task-based Gantt chart project management.

Organizations generally rely on software to efficiently plan, execute and track progress along the critical chain. Rather than tracking time elapsed from the start of a task to completion, critical chain software solutions include work queues and dashboards that monitor the rate of buffer consumption. If the rate of buffer consumption is low, the project is on target. If the rate of consumption is trending higher, then project stakeholders need to take corrective actions or develop a recovery plan to recoup the lost buffer. These buffer-rate consumption data allow project managers to set the appropriate project pace and conduct requisite resource-leveling activities.

Critical chain is a powerful way to reinvent your approach to project management to deliver projects on scope, ahead of schedule and under budget. Note, however, that you will have to make some important organizational changes to switch your project management methodology. To switch to critical chain project management, you must start by tracking project constraints and analyzing the effectiveness of your resources across a variety of tasks. You also need to evaluate the software you are using and take a fresh look at your planning process and project management style. Most important, you have to ensure that your company culture prioritizes resource dependencies along the critical chain, ignoring all distractions. Without these elements, it is easy to revert back to task-based project management styles.

Pamela Cargill / Chaolysti / Alameda, CA /

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