A man looks at a board outside Milan's stock exchange on July 11, 2011.
A man looks at a board outside Milan's stock exchange on July 11, 2011. - 
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Burton Malkiel is, as far as we're concerned, "The guy" when it comes to investment strategy. His 1973 book A Random Walk Down Wall Street has been reprinted multiple times. In it, the Princeton economist tells investors that they cannot outperform market averages. That they cannot time the market.

With pundits telling us that "stocks are cheap" right now, we decided to talk to Malkiel and get his point of view. He agrees that, relative to history, stocks are cheap right now, but he's adamant that nobody can tell you "this is the time to buy."

This is because just because something is cheaper than before is no guarantee it won't get cheaper still. One can imagine things that could knock stock prices down further.

Malkiel points to all the economic headwinds: high unemployment, dysfunctional government, Europe's debt crisis, etc. Malkiel says he believes the strategy he's long espoused is more relevant today than when he wrote the book. He's a fan of dollar cost averaging: investing equal amounts of money over specific periods of time in the same portfolio. The investor purchases more shares when prices are low; and fewer shares when prices are high. This way one lowers the total average cost per share in the investment.

One expert view, but one that's survived 10 editions of his path-breaking book.

Also on the show today, news that Americans are still considered around the world as "the coolest" nationality in the world sends the Marketplace Daily Index up two points today.

Follow David Brancaccio at @DavidBrancaccio