In order for stocks to improve, investors need to see the economic slowdown flatten out in the second half of the year, said Doll. If the rate of decline does indeed stall, investors could hope for a 'below-trend' recovery in 2010, he told CNBC's "Squawk Box." (See the accompanying video for more.)
"We can’t see, at the moment, light at the end of the tunnel," he said. "We need to see a resumption in the declines of credit spreads; we need to see a resumption in the velocity of money improving."
Commodity prices are also something investors should watch now, said Doll.
"If we have some more commodities flatten out, that's a sign that some parts of the world may not go into the big, black hole," he said.
The Chinese stock market seems to have benefited from its government's stimulus, said Doll.
"Let’s hope that that's a prototype that some of those things do work," he said.
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