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Context-led (SNAB) v concept-led approaches

Differences in what is covered in the two books: a message from Edexcel

Remember that a text book is only one author’s interpretation of the specification. A text book is an invaluable resource, but do remember to look at the specification too - this is what the exams are based on not the books.

The two Edexcel Biology books – for SNAB and for the concept approach – were written to cover the same level of basic detail. Both books also contain a certain amount of material designed to stretch candidates beyond the confines of the specification.

The context-led (SNAB) orange book extends students by considering further applications etc of the biology studied, and by extending the How Science Works opportunities.

The concept-led green book extends students by adding more detail of the Biology than the specification requires.

The revision guide was written by examiners and is common to both approaches. This is therefore a good guide to what in the two different books is examinable.


For the examination, it doesn't matter which approach students have studied – students on both concept and context approaches have the same specification. The students may come up with slightly different answers based on the approach of their textbook. Edexcel will ensure that the mark scheme has enough marking points to cover the answers which either student may produce. This mark scheme is likely to cover ideas which both concept and context students will write, but also correct biology unique to the style of teaching and learning the student has encountered.

Many questions relate to recall of the common areas of biology, or interpretation of graphs, or manipulation of data, or descriptions of practicals that, actually, the route is irrelevant. If we had an exam question which was 'Describe gene therapy', both concept and context students are likely to come up with the ideas of what it is. A concept-led student may then go into detail about gene probes, producing the replacement gene and delivering it to the patient. A context-led student may talk about the diseases in which it was used and the ethics of the process. The question is unrealistic, but I hope it shows that as long as the mark scheme allows more than one correct answer (which a good mark scheme always should), candidates can gain credit.

A suggested approach

Evidently, for financial reasons as much as for educational ones, schools will want to purchase only one textbook for their students. Do consider, however, getting at least a reference copy of the other sort of textbook for staff use and for the library. Look at the two different approaches of the book, alongside the specification, to make sure that you’re happy that the book you’re using with your students covers the specification to a level you’re happy with.

If there are discrepancies – you’re not sure whether certain details are needed or not – then there are two lines of enquiry open to you for checking. Firstly, look at the Revision Guide. Having started by saying that a textbook is one author’s interpretation of the specification, the Revision Guide has the distinct advantage that it is the Principal Examiners’ interpretation of the specification. Secondly, you can pose the question directly to one of the Principal Examiners by using the Edexcel Ask The Expert service, which you can find through the Edexcel website.

Damian Riddle

Edexcel Assessment Manager