With the Nasdaq retreating from its brief move above 5,000, investors need to see sustained, incremental improvement in earnings in order to feel confident about the market, investment professionals told CNBC on Thursday.  "People are gun-shy enough. Markets are fully valued, so you really need to see continuing, positive earnings growth. People are seeing mixed signals," said Alison Deans, CRT Capital's chief investment officer.  "My sense is it's a stair-step improvement in the markets now. They need to see globally incrementally positive news to want to spend more in the markets because markets aren't cheap—at least U.S. markets aren't cheap," she said in a "Squawk Box" interview.  Read More This is who the markets could be following  Markets are currently choppy and need to see earnings performance, Patrick Chovanec, chief strategist at Silvercrest Asset Management, told "Squawk Box."  While oil prices have stabilized, reducing anxiety over a free fall, the strong U.S. dollar remains a significant concern, he said. Forex headwinds have not only chipped away at corporate earnings overseas, but export competitiveness.  "The difference between 2 percent and 3 percent GDP growth if you look at the fourth quarter numbers is basically the widening trade gap. So the dollar is an issue," he said.  Read MoreThe stocks to buy when the smoke clears  While the prevailing sentiment that low oil prices will benefit earnings as consumers spend gas savings in the broader economy, Deans warned that Americas are coming out of a tough period of debt reduction.  She said a few months of lower prices at the pump will not spur them to spend as quickly as some suggest, adding that homes are still undervalued and wages have not increased significantly.  "We had [an oil] market correction. They had a lifestyle change, so I think that that creates a behavioral change and it takes longer term, feeling better about jobs, better about wages, and that this lower gas prices is a reality for the long term or at least for a couple of years."
Markets are fully valued, and investors are getting mixed signals, resulting in a pause after the Nasdaq hit 5,000, strategists tell CNBC.