Below is a video by Peter Navarro which explains how he uses a select group of international exchange traded funds to better help him time trades in the domestic market, in particular, the S&P 500 (SPY). The three international indexes he follows include the FXI (following 25 large and liquid Chinese companies, sometimes called the Dow of China - betting that as China goes, so goes Asia), the IEV (following the S&P Europe 350 Index), and the ILF (following the S&P Latin America 40 Index).http://link.brightcove.com/services/player/bcpid1079049304?bctid=27461401001
While I have not back-tested these specific indexes for providing leading signals, the video does remind us of the benefits of looking at other data for helping one to spot trends and even forecast movements in domestic indexes. A number of years ago I was engaged in some research that was looking to see if the S&P 500 could be used to help predict trends in various international indexes. After all, the feeling was that as the U.S. goes, so goes the rest of the world - or so we assumed. As our research progressed, and we began doing correlation studies, principle component analysis, information-based data mining, and everything else we could throw at the problem, it became clear that in many instances we had it backwards. The international indexes were more predictive in helping forecast the U.S. market. While some of these correlations broke down over time, it nonetheless helped send the message that we could not assume that the U.S. markets were always driving the world markets, or that the influence was always consistent, in either size or direction. While this is more clear today, and less of a surprise, it still seems as though few traders and investors use such information. The three international ETFs mentioned above are a good place to start your own studies.