When you go to the doctor, you expect a solution to why you’re sick. A good doctor doesn’t run one test and then say to the patient, “Well, you didn’t get any better. I’m not sure how to help you, so we’ll just let this play out and hope for the best.” That would be horrible.
This idea translates well to the field of education. Educators should be like good doctors; they must teach a concept, assess, teach again in a different way (if necessary), and continue the process until the student has learned–just like an effective doctor should treat a patient, assess the results, treat again, assess, and so on until the patient is well.
The years of teaching important concepts once and then moving on, regardless of who did or didn’t learn, are over.