The lure of successful trading strategies is seductive, and looking at your portfolio shrink in value during a market downturn can be painful. But many times investors seeking to circumvent the pain or trying to get a leg up in their investments by temporarily shifting away from their long-term strategy will end up trading one source of anguish for another.

Stock prices are soaring as the economy struggles. Does this mean the market is overvalued and about to fall? What should you do?

All news is old news. Invest looking to the future, rather than base your decisions on outdated data.

There will never be a perfect time to invest. But the longer you wait, the more it will cost you.

How do you sieve through the mass of confusing investment advice?

Can investors consistently time the market? Will you be able to tell when to buy or sell? In this video, Jim Davis from Dimensional Fund Advisors runs more than 780 tests on data from 15 stock markets to see what the evidence says.