Riding a wave of voter frustration with the economy and anger against federal deficit, the Republicans are poised to gain big in next week's mid-term elections, as polls show they have the edge over the Democrats in the race for control of Congress.

The Republicans are also heavily favored by predictions, as pundits predict they could gain up to 50 seats in the House of Representatives. Thomas Mann, a political expert in the Brookings Institution, explained in an analysis that there are three factors that give the Republicans an edge in the elections.

The first one is that the president's party traditionally loses seats in the House in mid-term elections. Fred Beuttler, the chamber's deputy official historian, said there are only two exceptions in the past century, which were elections in 1934 and 2002.

"It's sort of a normal case where you would see the president losing seats in the House of Representatives," Beuttler said during a recent session with Washington reporters.

The second point, Mann said, is that the Democrats won big in Congressional elections in 2006 and 2008, with some of the newcomers struggling to hold on, especially those in traditional Republican territories, and all but abandoned by the Democratic leadership.

"Democrats are now, as a result of their victories in 2006 and 2008 when they picked up a net of 50 additional seats, they're really above their natural strength. They're holding congressional districts that have traditionally voted Republican in presidential campaigns, so they're vulnerable. They have to defend a large number of seats with conservative Republican constituencies," said Mann.

The last and most important factor is the state of the economy. The state of the economy is in a bad shape, with high unemployment and sluggish job creation, creating "a great sense that nothing is working in this country. People are very bleak about the state of the economy."