A bearish example for this comparison was seen in late September 2008 when QQQQ started to fall behind SPY at a quicker pace.

It’s interesting to consider this and Hart makes a good case for at least watching what these funds do. To find specific areas in the market that are moving, we suggest a simple strategy such as trend following. To read more, check out our special report.

For more information on following the trends, visit our trend following category.

Max Chen contributed to this article.