The political world fell in love with Twitter during last year's presidential campaign, when Democrats and Republicans used the digital messaging service to argue about the campaign, the debates, and the truth of candidates' statements.
The Pew study shows that attempts to gauge overall trends on Twitter, in most cases, was disconnected with polling research conducted nationally.
For example, when public opinion surveys showed that 52 percent of people were satisfied with President Barack Obama's win over Mitt Romney, Pew estimates that 77 percent of Twitter reaction was positive about President Obama's win.
But Twitter doesn't always lean toward the liberals.
Public polling showed that about 48 percent of people had a positive opinion of President Obama's inaugural address in January; among Twitter users, only 13 percent of users had a positive opinion of the speech.
Of eight major events tracked in the past year by Pew, only one had similar popularity results between major public opinion polls and Twitter: Paul Ryan's selection as Romney's running mate.
A second, the Supreme Court's health care decision, was at least close when it came to negative reaction. The difference was only 8 percentage points between a national survey and Twitter. (However, the difference was 16 percent points among people who had a positive opinion of the health care decision.)
Pew's conclusion is that the audience that uses Twitter doesn't reflect the general adult population when it comes to politics.
"The lack of consistent correspondence between Twitter reaction and public opinion is partly 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," it says.
Another issue is that Twitter is heavily used, but only by a small percentage of the population. Pew cites data that shows only 13 percent of adults use Twitter or read Twitter messages, and only 3 percent of people get their news from Twitter.
Twitter also tends to have younger users who also tend to be Democrats.
The findings aren't likely to stop politicians who have become obsessed with Twitter and have made a considerable investment in building up a huge number of Twitter followers.
President Obama can claim to have more than 25 million Twitter followers, according to the website Fanpagelist.
Obama's Twitter efforts far outshine other American and global politicians. Arnold Schwarzenegger and Al Gore have more than 2 million followers, and John McCain tops the Republicans with 1.8 million. The Dalai Lama has more than 6 million followers.
And in some cases, Twitter can hurt politicians. On Tuesday, McCain was defending himself after a tweet from his account compared Iran's president to a monkey.
The most famous Twitter mistake came from former political rising star Anthony Weiner, who accidentally posted a lewd photo of himself on the microblogging service in June 2011.
Weiner is now out of the political limelight, but he returned to Twitter last November.