PPP first entered prominence through its performance in the 2008 Democratic primaries between Barack Obama and Hillary Clinton. The company performed well, producing accurate predictions in states ranging from South Carolina to Wisconsin, many of which featured inaccurate results by other pollsters.[non-primary source needed] After the November election, PPP was ranked by the Wall Street Journal as one of the two most accurate firms, among those who were most active in the presidential swing states.
PPP was the first pollster to find Scott Brown with a lead over Martha Coakley in the Massachusetts Senate special election; Brown ultimately won in a major comeback, and PPP's final poll in that race predicted Brown's winning margin exactly.
PPP was praised[by whom?] for its accuracy in polling primaries and special elections, which are notoriously hard to predict. The contests they accurately predicted include the West Virginia gubernatorial primaries, special elections in New York and California, as well as all eight Wisconsin recall elections.
A study by Fordham University found that, of 28 firms studied, PPP had the most accurate poll on the presidential national popular vote, both its independently conducted poll and the one it does in collaboration with the Daily Kos and the SEIU. PPP correctly called the winner of the presidential election in all 19 states it polled in the final week of the election, as well as the winners of all the U.S. Senate and gubernatorial races it surveyed.
Political research firm YouGov found PPP’s gubernatorial polls to have the lowest average margin of error among national firms that polled in at least ﬁve gubernatorial races in the month preceding the election.
In 2013 columnist Nate Cohn described PPP as a liberal pollster, although according to statistician Nate Silver, PPP had a tendency to slightly lean Republican as of September 2016. As of February 11th, 2017 Silver's website, FiveThirtyEight, gives PPP a B+ grade in its pollster ranking.