Experts are closely monitoring Google search data and social media for hints about the outcome of the U.K.’s historic referendum on European Union membership Thursday.

Opinion polls have suggested a tight race in the vote on the country’s future.

Google UK search data early Thursday show a significantly higher number of searches for leaving, compared to staying in the E.U.

However, social media expert and President of JRM Comm Jason Mollica told FoxNews.com that search data is just “one piece of the puzzle.”

“I think what we’re seeing is that people are very passionate about [the referendum] – they want to be sure that they are making an informed decision,” he said.

Mathematician Nikos Askitas notes that Google search can provide good insight into voter intent. “The demand for one kind of information or the other reveals facts about the state of the individuals and search is the act of expressing that demand,” he wrote, in a blog post Wednesday.

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The expert noted that many - but not all - of the top referendum searches are related to voting intent. Using a combination of Google search data and his own calculations, Askitas predicted Thursday that 52 percent of referendum voters will opt to remain in the E.U.

The Washington Post reports that Askitas performed accurate analysis of Ireland’s referendum on same-sex marriage and the Greek referendum on economic policy.

Social media trends related to the U.K. referendum are also being closely watched.

On Monday Twitter U.K. noted that more Tweets were sent about ‘Leave’ than ‘Remain’ in the prior week, but added that, for only the second week, the latter had more accounts tweeting.

Google memorialized murdered British politician Jo Cox in a post this week, and urged people to donate to her memorial fund. The death of the Labour Party politician, who would have celebrated her 42nd birthday Wednesday, brought a shocked pause in campaigning for the E.U. referendum.

Follow James Rogers on Twitter @jamesjrogers

The Associated Press contributed to this report.