Google’s decision to skew its search results in favor of its own services hurts users, a study released Monday claims.

The findings are sure to add a new layer to the company’s ongoing antitrust battle in Europe. The paper, written by Columbia Law School’s Tim Wu and Harvard Business School’s Michael Luca, is backed by Yelp, which has filed an antitrust complaint against Google.

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The paper finds there is evidence to suggest that users would rather view search results from across the Web rather than those selected by Google from its own proprietary databases.

Currently, Google responds to some searches by displaying results from its own services. If, for example, a user searches for coffee shops in their area, they are likely to first see a list generated from Google’s database of local businesses.

Competition advocates claim this hurts users and Google’s competitors. Other companies say they lose out on traffic if their pages are ranked lower on the search engine.

The study found users are 45 percent more likely to click on local search results if they are “organically determined” — meaning that they do not prioritize Google’s services. The authors say that this shows that Google is harming consumers with its current practices.

“This suggests that by leveraging dominance in search to promote its internal content, Google is reducing social welfare — leaving consumers with lower quality results and worse matches,” the authors write.

In both cases, the results were displayed inside Google’s “7-pack,” a unit that gathers seven top results and is generated for many local searches.

For the study, the authors used a sample of 2,690 users on the platform Mechanical Turk.

The study focuses on local search results, the market Yelp competes with Google in, and the authors found that there are other cases where Google’s search tools are helpful to users.

A spokesman for Google argued the new study is based on a "flawed methodology."

"This isn't new - Yelp's been making these arguments to regulators, and demanding higher placement in search results, for the past five years," a Google spokesperson said in a statement. "This latest study is based on a flawed methodology that focuses on results for just a handful of cherry-picked queries. At Google we focus on trying to provide the best results for our users."

The tech company faces challenges to its practices from antitrust regulators in the European Union. In April, Margrethe Vestager, the EU’s antitrust chief charged the company with prioritizing its own results at the detriment of its competitors. She said last week that the company still had time to respond to the charges.

Wu defended the study's integrity, despite the fact that he was compensated by Yelp for his work. Wu is a top scholar in the field of antitrust.

“They are paying me for my time,” he told Re/code. “But I wouldn’t be doing this if I didn’t think this new evidence was a game-changer.”