之前讲义里面有讲alpha的来源是择时 timing
但是后面这个课后题里面的答案却又说是 security selection skills,exposure to rewarded factors,以及factor timing。那么这个答案为啥比讲义里面说的factor timing这个原因还多增加了两个原因?怎么理解呢?麻烦辨析一下
还有,什么叫factor timing 呢?是选择exposure to factor的时间点是吗?
那么到底是factor timing 还是factor exposure (exposure to rewarde factors)能产生alpha呢?