王同学2019-01-25 13:29:57

Reading50里面的EXAMPLE 9的问题2的解答没有看懂。 题目是Suppose the investor predicts Assets #1 and #2 to outperform and that Assets #3 and #4 will underperform. Conceptually speaking (i.e., exact numbers are not necessary), how will these scores affect the information coefficient in the fundamental law compared with a prediction that Assets #1 and #3 will outperform and Assets #2 and #4 will underperform? 解答是According to the risk model, the active returns to Assets #1 and #2 tend to move together, so a forecast that both will outperform is not as ambitious as a forecast that one will outperform while the other underperforms. As a result, the information coefficient will be adjusted downward by more under the first set of forecasts than under the second set of forecasts. 我不明白的问题有两个：第一，为什么IC会be adjusted downward；第二，为什么ambitious的IC大，不ambitious的IC小？谢谢老师