We always teach clients estimation technique first, followed by brainstorming technique and finally full case technique. There is a simple reason for this, which is explained in this podcast. Estimations tend to be, but not always, a brainstorm with very few or just one branch. A brainstorm is therefore an estimation equation with multiple branches. A full case structure is a very large brainstorm with mini-brainstorms at each new branch. We want candidates to see this evolution so they can understand how crucial brainstorming is to the entire case interview approach.