It looks like the core reading is different to the diagram in section 7.2 of chapter 17. The diagram shows the gains curve as being a plot of cumulative fitted values against cumulative exposure. However the accompanying text says the chart shows the cumulative fitted value and the cumulative observed values. I suspect the core reading is wrong here. Any thoughts, anyone?
Thank you for drawing our attention to this. For the benefit of other students reading this, the curve in question is the very faint line above the straight diagonal line on the diagram on page 42 of chapter 17 in the CMP. The graph and text are both part of the Core Reading. I agree that the text appears to be describing something different from what is shown in the graph. I would expect the y-axis to relate to observed data. I'll ask the Profession to clarify how students should interpret this graph for the purposes of the exam. Duncan
I have already contacted the Profession again about this. I was assured on Monday that it is being looked into. I will let you know as soon as I have a reply. Sorry I can't be of more help at present. Duncan
I haven't received a definitive answer but what the Profession has said is that the examiners will be made aware of the issues. Students will be given marks for either an incorrect approach which follows the Core Reading or a correct approach which contradicts the Core Reading. In other words, if this does come up, it will be marked fairly, allowing for any problems in the Core Reading. The examiners have the Core Reading and are also experts in the subject. I believe that the correct approach is to show the cumulative observed on the y-axis, with a good model having a high Gini coefficient. Duncan
