Question ladders
A single good question is useful. A sequence of them is what actually moves understanding, and the sequence has a shape: establish what is known, test whether it is understood, then push until it breaks.
The third rung is the one people skip. Deliberately looking for the case where your own explanation fails is uncomfortable and is where nearly all the value sits.
Working against yourself
Ask the question you would rather not: How much of this outcome was your reasoning, and how much was variance? Then argue that case properly rather than dismissively.
In practice, across chart reading and risk management, this is what separates someone who has memorised a method from someone who knows when it does not apply.
Transfer, which is the real test
Understanding that only works in the form it was learned in is not understanding — it is pattern matching with good manners.
So the exercise is to take the idea into an unfamiliar context and see what survives. What breaks tells you which parts were scaffolding.
Self-assessment without kidding yourself
The honest check is whether you can teach the idea to someone who will interrupt with awkward questions, without notes.
The dishonest check is recognition: reading an explanation and feeling that it makes sense. That an outcome proves the reasoning behind it was sound is the same error wearing a different hat.
Practising deliberately
Set a standard before you start, not after: writing down the reasoning and the risk before the outcome is known, then reviewing the reasoning rather than the result. Reviewing against a standard you chose afterwards is not review.
You will know it is working when the learner separates a good decision from a good outcome without prompting.