Most teams treat a premortem as a planning exercise. Imagine the project failed. List the reasons. Feel sober. Then go build the thing you were always going to build. Duke's observation is that this is what happens: run a premortem and people do not change their plan much. The insight evaporates, because nothing forces it to survive contact with a decision.
Her reframe is to treat it as a signal generator. The output you want is not a revised plan, it is a list of things you would observe on the way down. Each becomes a kill criterion: a measurable condition meaning stop or pivot, written while you have no stake in the answer.
It has to be structural, not intentional. Once you launch, the biases pointing at continue outrun your resolve. Sunk cost is the loudest. Duke's inversion: waste is forward-looking. You cannot get back what you already spent; the real waste is the next six months poured into something you know is dead.
So the framework is not think harder about risk. It is convert the risk you already imagined into named signals, and pre-commit to what you will do when each one appears.
