Priya has just earned her Black Belt. Her first project, cutting rework in invoicing, has clean data, a clear charter and a sponsor who nodded in the kickoff. Six weeks later nothing has moved: two team members skip meetings, the process owner calls the findings "interesting", and the sponsor has stopped replying. The data was never the problem. Six Sigma leadership is the skill set that rescues a project like this, and this guide sets out what it consists of.

Why do Black Belt projects stall on people rather than on data?
A Black Belt is trained to find the cause of variation, so the first instinct when a project slows is to look for another cause in the numbers. Usually the numbers are fine. The project has slowed because someone whose cooperation it needs has not been convinced, informed or given time. The tools of improvement work cannot fix that, because they describe a process, not the people who run it.
Three features of the Black Belt role make this common. First, the work crosses departments. A rework problem in invoicing touches sales, who write the orders, the warehouse, which ships them, and finance, which bills them. None of those groups reports to the Black Belt. Second, the project asks people to give up hours that already belong to something else. Third, a successful project changes somebody's daily routine, and the people whose routine changes are rarely the people who asked for the project.