"Much of the difference may have to do with both the narrow sliver of the public represented on Twitter as well as who among that slice chose to take part in any one conversation," the study's authors said in their report.
Using a computer software programme that analyzes the context of social media posts, the year-long Pew study compared social media data with public opinion surveys focused on eight major American news events including the 2012 presidential election, debates, and speeches by US President Barack Obama.
In the majority of the cases examined by the Pew Center, Twitter correspondence was inconsistent with public opinion, "a reflection of the fact that those who get news on Twitter - and particularly those who tweet news - are very different demographically from the public", Pew researchers said.
For instance in February 2012, a US federal court ruled that a California law banning same-sex marriage was unconstitutional, researchers found that 46 percent of the reaction on Twitter was positive with only eight percent of Tweets reflecting a negative tone.
But public opinion surveys measured in a Pew national poll had a very different outcome. Of those who had heard about the ruling 44 percent indicated they were disappointed or angry with the judgment while 33 percent of respondents said they were pleased with the outcome.
Few researchers found this trend remained true during the 2012 presidential campaign.
During the first presidential debate when polls showed Republican contender Mitt Romney gave a better performance than Obama, the tweets about Romney were much more critical according to a Pew analysis of social media reaction.
Social networking sites including Facebook and Twitter are primarily made up of younger users with a pro-Democratic lean, the Pew Center found. But when it comes to tweets, that bias is not always apparent, as overall negativity tends to dominate conversations.
"The reaction on Twitter to Obama's second inaugural address and his 2012 State of the Union was not nearly as positive as public opinion," researchers reported.
The lack of consistent similarities between Twitter reaction and public opinion is why media industry experts caution news outlets against providing social media reaction without additional context.
"We can certainly talk about the Twitter reaction, but we can't generalize it," Regina McCombs, a member of the multimedia and mobile journalism faculty at the nonprofit journalism school, The Poynter Institute, told RIA Novosti.
"Only 85 percent of people in the US use the Internet," said McCombs, adding that only 16 percent of those users are on Twitter. "We just shouldn't use it as a proxy for what everyone is thinking," she said.
Of the eight events the Pew Center tracked, there were only two cases where the Twitter reaction mirrored public opinion: Romney' selection of Rep. Paul Ryan as his running mate and the Supreme Court's ruling on Obama's Affordable Care Act, overhauling the US health insurance system.