What Do Doctors Have In Common With Increasing Your Consultancy Income? By: Alistair Grieve | - A proper Diagnosis leading to the correct Prescription is crucial if you want to cure the patient. I first came across the term "Diagnose before you Prescribe" in Keith M. Eades book "The New Solution Selling". One of the core concepts of the book is that all Great Sales People must also be Great Consultants and it is important to first Diagnose the Situation before you Prescribe a Solution.