Zhuoling,

Great question, almost deserving a separate post. Before then, here is my quick response:

First, many investment professionals, including those referenced here in this article, would want to look at performance issues including style drift over the longer term. So how long is long term? Hard to say exactly but generally longer than a quarter or even a few quarters.

Second, there's a tendency to over specify styles - in the second article in this series, one panelist mentioned that they had 39 aset classes at one point. There are tools that would treat asset classes as styles. If we are talking about 39 styles as a result, it is not very meaningful because many of the 39 asset classes are driven by the same factors.

Once we are sure that we are looking at a reasonable set of factors over a long enough period, then any style shift still present needs to be carefully evaluated against the manager's stated objectives. Intentional style shift that improves returns is an integral part of dynamic asset allocation programs. For managers who claim they attempt to stay within a style box, then they clearly have not delivered on their promises.

Thanks again for the question and for your help in promoting our content among your friends.

Larry