Gettiers in software engineering (2019)

The "programmer's model" is their mental model of what's happening. You're senior and useful when you not only understand the system, but can diagnose based on a symptom/bug what aspect of the system is implicated.

But you're staff and above when you can understand when your programming model is broken, and how to experiment to find out what it really is. That almost always goes beyond the specified and tested behaviors (which might be incidentally correct) to how the system should behave in untested and unanticipated situations.

Not surprisingly, problems here typically stem from gaps in the programming model between developers or between departments, who have their own perspective on the elephant, and their incidence in production is an inverse function of how well people work together.

You are defining valid steps in understanding of software, but attaching them to job titles is just going to lead to very deceptive perspectives. If your labeling was accurate, every organization I've ever worked at would at least triple the number of staff engineers than it does.