How to avoid misunderstandings when communicating student progress to parents at tutoring centers

I previously fell into this trap when providing monthly feedback at an after-school tutoring center: the teacher felt the student had improved, but the parent only saw that the grades hadn't gone up and started questioning whether the course was effective. At the time, if I had only dealt with the most obvious surface-level issues, it might have seemed fine in the short term, but it would…