The survey found 55 percent of Republican and Republican-leaning respondents said they expect GOP candidates to fair better than they have in recent elections, Pew said in a report released Friday.
Democrats are less confident: 43 percent of Democrat-identified respondents said they believe their party will do better than in recent elections.
Meanwhile, voter enthusiasm is about the same going into the midterm elections as in years previous. About 49 percent of registered voters said they are very enthusiastic about voting in next year's elections while 19 percent said they are not excited at all.
Currently, 48 percent of respondents said if the elections for U.S. Congress were being held today, they would vote for Democratic candidates,while 44 percent said they would vote Republican. These findings have changed little since October, Pew said.
The poll was conducted Dec. 3-8 among 2,001 adults nationwide. It has a margin of error of 2.6 percentage points.