I find it interesting that the current PMBOK dedicates 64 pages to risk management, and yet I cannot find the word “inhibitor” anywhere in the entire document. (Note: this is not a derogatory comment about the PMBOK).
It is my experience requiring resources to report inhibitor status on active tasks each working day, is a great source of information for the risk management plan. This information is active work performance data and can be included in work performance reports.
It is important to know if there is anything slowing the progress of a task, and it is better to know sooner than later.
A single task can have multiple inhibitors, and each inhibitor can have a different effect in slowing the progress of the task. Inhibitors accumulate and no single inhibitor is too small to ignore.
When you ask your resource if there is anything slowing their progress, they see that you are paying attention and care about their success. You can demonstrate your commitment to them by making plans to do all you can to eliminate their inhibitors.
When an inhibitor is identified I ask — what is the impact? I express impact in terms of percent; 0% is no impact, 50% is causing the task to take twice as long to finish than planned, and 100% is total impact — that is to say no progress can be made on the task.
On a task-by-task basis I sum all of the current impacts and use the total to identify which tasks are at the greatest risk of finishing late or not finishing at all.
I also ask if there are any potential inhibitors that could happen in the future, and if so, what would be the impact, and when they might occur. This is a great way to provide ongoing input to the risk management plan by identifying potential risks.
I developed these techniques in response to lessons-learned from failed projects. I found that many problematic projects had significant inhibitors that were reported late or not at all.
