Most candidates will then start to generate a, more or less structured, list of concrete ideas – shooting essentially from the hip (e.g., “They could invest into more teachers!”).
Some candidates will take some time to bucket these ideas into categories (“There could be short term measures and long term measures. Short term measures could for example be blablabla…”). This is a bit better – but still far from good!
You have to realize that brainstorming is not just about the ideas themselves (in fact, it is not even primarily about the ideas!), but first and foremost about HOW you generate these ideas! You want to demonstrate the rigor of your thinking, as well as the ability to outline and articulate this thinking in a sharp way.
So here is how a very strong candidate develop his answer to this brainstorming question (please look at the diagram below!):
Step 1: Outline the precise question – “How can we improve primary education in country X?”
Note that this question is impossible to answer before having precisely defined, what “quality of primary education” actually means! It could be number of children going to school… Or number of graduates produced by the system… Or how good the pupils are… etc. A blurry question like “How to improve…” MUST be defined! And it is the candidate’s duty to nail down the interviewer on the definition of what we are solving for – the FOCUS METRIC!
So let’s assume, the interviewer confirms that the focus metric is “number of children going to school”. Only now we can proceed!
Step 2: Disaggregate the question – build the logic tree and identify what drives the answer to the question.
So we could imagine that the primary reasons for NOT sending children to school would be of financial nature, logistical nature, and potentially cultural nature. Then you develop the tree into a set of sub-branches which further disaggregate these three categories into sub-reasons. If we can do something about these sub-reasons, then they are “levers” which we can pull!
Step 3: Develop ideas – NOW is the time for the actual ideation! Outline concrete examples on the actual measures which could influence each lever into the desired direction.
THIS is how you brainstorm! Define the focal question, disaggregate this question into its constituting elements, and then outline concrete examples underneath each (sub-)element which could answer the main question.