Reversion to which mean?

Timing is all. But can trends and signals help getting the buy and sell timing right? Elroy Dimson, emeritus professor of finance at the London Business School and joint author of the Credit Suisse Global Investment Returns Yearbook 2013 tells Long View columnist John Authers about the risks of exiting the market, even it seems due to revert to the mean.

For more video content from the Financial Times, visit http://www.FT.com/video