“Interestingly, Agile’s scrum-team approach has its own way of aggregating some execution risk. For example, in a traditional “single task owner” approach, the risk of execution is not aggregated at all, leaving that task owner to add a lot of task-level buffer to self-insure and deliver on his commitment. In contrast, a 5-person scrum team aggregates the risk that any single individual will make slow progress, as the other four team members can often make up the deficit.

But why aggregate only up to the scrum-team level? Taking a lesson from the insurance industry, the more that risk can be aggregated, the easier it is to manage. Applied to projects, this will nearly always mean that it’s better to aggregate risk at the project level. As a result, an Agile project can improve speed by avoiding sprint-level commitments.”