Training needs analysis: how do you separate a training gap from a process gap?

Training is the default answer to an incident, an audit finding and a customer complaint. It is also the wrong answer whenever the person already knew what to do and something in the work stopped them doing it — a tool that was not available, a procedure that does not match the plant, a target that rewards speed. The simple test: if you could put the same person back in the same situation with perfect knowledge, would the outcome change? If not, training will not fix it. How do you make that argument to a client or a manager who has already announced a training plan?