Critical Chain changes the way tasks are managed. Daily status helps to keep people’s attention on one task. Asking the person for remaining duration has them thinking about what they still have to do. It also becomes a subtle commitment for them.

Project status is current and reasonably accurate. Buffer Management identifies the tasks that are most impacting the project due date. The most important tasks get priority and focus to get them done. Problems show up quickly so they can be dealt with. Projects get done fast and the people doing them like it.

I think you have only scratched the surface of Critical Chain. Scratching is good!

Critical Chain Project Management (CCPM) is based on the Theory of Constraints (TOC).

TOC was designed first for production with a management method called Drum Buffer Rope (DBR).

These two methods are fundamentally the same, but have different approaches. Both production management and project management apply to resources, tasks, dependencies and deliverables.

I was a manufacturing engineer with Boeing in Seattle for 14 years. Building an airplane could be managed as a project or production. They are one of the world’s top users of TOC. Building an electrical power unit could be considered production or a project.  Beer cans would be production.

To me, the difference is in how you want to pay attention to it, manage it. If it’s valuable, important or time critical, manage it as a project so you know how it’s doing all the time. If it’s repetitive, high volume, or time flexible, manage it as production. Between the two is a huge grey area and choice.

http://ccpmconsulting.com/category/operations/ and http://ccpmconsulting.com/category/project-management/

Production usually has significant queue time between operations. Projects have far less slack between tasks, and none along the Critical Chain/Critical Path. CCPM and DBR both focus attention on the system constraint. The theory is that every system has something that limits it, a constraint. There is usually only one. Find it, help it, and get immediate and significant improvement in output. It is easy to use and decisions become obvious. It’s worth a good look.

Once the Critical Chain (CC) is identified, it becomes the baseline to measure project progress. A stable CC is therefore a requirement.

The Critical Chain is only recalculated or revised if there is very significant new work added to the project.Then progress must be measured to the new CC.

CCPM compares the percentage of Project Buffer consumed to the percentage of the Critical Chain that has been completed. (This is based on the time used versus the work completed.) This ratio is a direct indicator of the project health. If the buffer is consumed faster than the critical chain is being worked, management attention may be needed.

An estimate of a task’s duration can be derived from historical data, expert knowledge and even guessing. Most estimates make allowances for “stuff” that often occur. Things going wrong, other things to work on, distractions and …? Historical data may be available for a task that has been done many times.

The estimate is put in project management software which gives it a start and finish date. The estimate becomes a due date, a deadline. People work to meet deadlines. Deadlines make it difficult to get done early.

I used to work to a due date report for my projects. The project durations were based on standards set by the company. Whichever of my projects was nearing its due date got my immediate attention. I almost always finished them on the due date. It was amazing how those standards had such accurate durations.

I suggest that the duration estimate is a number that is useful for planning the project. During project execution, it becomes a deadline.