Back when I was a product manager, there was an engineering manager who would drive me crazy. He had this idea of a 90% schedule, by which he meant a 90% chance of hitting if everything went as planned. Everything never went as planned.
He probably read Goldratt's follow-on to The Goal, Critical Chain. Critical Chain Project Management is the specific term. Goldratt tried to sell software to companies that would help them make schedules like that, but a large component (often ignored) was collecting historic data, and running models. Most companies might do one of those, but rarely both, and of course models with only speculative numbers are absolute garbage. In my experience, places that tried to apply CCPM never actually grokked it, and it was some manager's obsession because they were buzzword crazed (like many big-A Agile offices).
