You are an experienced project manager who has been assigned to lead a large

You are an experienced project manager who has been assigned to lead a large

You are an experienced project manager who has been assigned to lead a large, mission-critical project with a deadline which can not be extended for any reason. It was decided to use a predictive life cycle for the project. Your project team and stakeholders have collaborated well and worked hard to define requirements, create a well-defined work breakdown structure, sequenced activities and estimated effort and durations for all of them.
You’ve integrated all of the information your team has generated into a proposed baseline schedule using scheduling software, applying your understanding of scheduling best practices. You’ve presented that schedule to the project steering committee for their review and approval. You thoughtfully scheduled a formal schedule review meeting for the steering committee at which you intend to address their questions and issues.
Shortly after the meeting starts, one of the stakeholders raises a hand to ask a question. “This is the first time I’ve ever really looked closely at a project schedule. Thanks for your effort in creating it, as I can see from the number of activities that it must have taken a lot of effort,” he begins.
“There’s one thing I don’t understand, though. It looks like you’ve included a number of activities in one sequence which don’t refer to actual work being done. You’ve labeled each of them as ‘Buffer’. If I add up all of the calendar time for all of those buffers, it seems to extend the project’s overall duration by three weeks. Why would you do that?”
How would you respond?