Several U.S. senators accused Google of giving search preferences to its own suite of services over competitors, but Executive Chairman Eric Schmidt denied that his company is manipulating search results during a hearing Wednesday.

Google's search results appear to be biased in favor of its shopping results and other services, and Google's own services always seem to appear near the top of its organic search results, said Senator Mike Lee, a Utah Republican.

Lee referred to a chart showing Google's shopping results consistently in the top three search results, while other comparison shopping sites moved up and down in Google rankings. It appears that Google has "cooked" its search results, he said.

Schmidt denied the assertions of Lee and other subcommittee members. "I can assure you, we haven't cooked anything," he said. Google is focused on delivering the best search results, not driving business to its services, he said.

Lee's chart appeared to be comparing searches for products with searches for price comparison sites, Schmidt said. "I'm not aware of any unnecessary or strange boosts or biases" favoring Google products, he said.

That answer didn't satisfy Senator Al Franken, a Minnesota Democrat. Schmidt's answer to Lee, saying he wasn't aware of any search bias in shopping services was "fuzzy," Franken said. "If you don't know, who does?" he added.

Schmidt's answers didn't seem to assure Lee, either. Schmidt's answers confirmed his "fears" of Google search bias, Lee said.

Google Rankings

Questioned about the rankings for some small businesses rising and falling in search results, Schmidt told senators that Google tweaks its search results about 500 times a year. Google is providing a good service for the "vast majority" of small businesses in the U.S., he said.

"Not every website can come out on top," Schmidt said. "For every winner, there's a loser."

Google's search business model seems to have changed in recent years after an "acquisition binge" has brought the company into several new markets, said Senator Herb Kohl, a Wisconsin Democrat and subcommittee chairman.

Senator Richard Blumenthal, a Connecticut Democrat, compared Google's early business model to a company that owned a racetrack but then began owning horses. "Your horses seem to be winning," he said.

Executives with consumer review site Yelp and comparison shopping site Nextag told senators Google's search practices are hurting their businesses. Instead of innovating, Google has copied other services in creating its own shopping site, said Jeff Katz, CEO at Nextag. About 65 percent of Nextag's search results come through Google, and recent changes to the Google search results have dramatically hurt his business, Katz said.

Google was a good partner for years, but it has recently begun to favor its own services over Yelp, said Jeremy Stoppelman, Yelp's cofounder and CEO. Google in recent years has focused on being a destination site, not an unbiased search engine, Stoppelman said.

Stoppelman questioned if Yelp could succeed today, under Google's current practices. Asked if he'd start Yelp in the current environment, Stoppelman said, "I'd find something else to do."

But Google users can easily choose another search engine or other services, if they don't like the end results, said Susan Creighton, a partner with the Wilson Sonsini Goodrich & Rosati law firm and an antitrust adviser to Google. Amazon.com provides a huge product search service and Facebook has a large local advertising service, she said.

"It's free and instantaneous to try someone else's search results," she said.

Creighton, the former chief antitrust enforcer at the U.S. Federal Trade Commission, warned senators about attempting to tell Google how to deliver search results. Government interference could turn Google's search results into a "regulated utility," she said.

Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is grant_gross@idg.com.