(Note that I currently teach the Edexcel A-Level and this advice is geared to that)
When writing your longer answer questions there is sometimes a debate as to whether or not a definition is required. Whilst it is quite possible to get the knowledge marks in a question without a definition, I am an advocate of it for most questions.
My suggested structure for pupils answering 8, 10, 12 & 20 mark questions is to start with a conclusion provided that:
1. You know what to define straight away
2. You can make that definition short and succinct
The definition will help with accessing a knowledge mark for the question and also (perhaps more importantly) in getting you thinking about how your answer relates to that knowledge and what the question is asking of you.
As with all the suggestions I give to my pupils on structure, if you find yourself in the time pressured environment of an exam and can’t come up with a definition – then move on. You are looking to maximise your marks and your potential, the structures I suggest are recommendations that have worked for a number of pupils over time but there is never an exact one size fits all approach.
A Level Business Goat 