Thought i should point out that the John Ewbank grading system encompasses a range of factors, including sustainability,degree of difficulty technical and physical,and exposure. the exposure factor includes a number of features including adequecy of protection,fear factor and even isolation and evacuation difficulties.The John Ewbank system attempts to encompass all of the features of the English grading system it was developed to replace into a single number system, in part to address the previously mentioned complications of the english grading system.