"Work harder next month."
I have heard it in many reviews. I have said it myself, early on. It is not a plan, because it does not say what went wrong.
In my experience, most missed months come down to one of four causes. Each one needs a different fix.
Coverage. Are the right doctors on the list, and are they actually being seen? If not, rebuild the list with the rep, by potential.
Frequency. A doctor seen once a quarter does not remember you. Fewer doctors, seen more often, usually does more than a longer list.
Message. The doctor is seen often but is not convinced. That is a coaching job. Watch the call and work on one skill at a time.
Stock. The doctor prescribes, but the product is not on the pharmacy shelf. Check distributor stock and raise it the same week. That one is often the quickest to fix, and the easiest to miss from behind a desk.
I go through all four with the rep before we decide anything. Usually one of them explains most of the gap, and the rep often spots it before I do.
“Name the cause before you choose the cure.”

Lesson 6 of 13 in Step 2: Targets, forecasts and numbers, with the full guide and a checklist for this week.