Gallup’s full briefing can be found here.  Below are some of the highlights:

“Gallup’s analysis of several indicators of voter turnout from the weekend poll suggests turnout will be slightly higher than in recent years, at 45%. This would give the Republicans a 55% to 40% lead on the generic ballot, with 5% undecided.”

“Taking Gallup’s final survey’s margin of error into account, the historical model predicts that the Republicans could gain anywhere from 60 seats on up, with gains well beyond that possible.

“It should be noted, however, that this year’s 15-point gap in favor of the Republican candidates among likely voters is unprecedented in Gallup polling and could result in the largest Republican margin in House voting in several generations. This means that seat projections have moved into uncharted territory, in which past relationships between the national two-party vote and the number of seats won may not be maintained.”

“President Obama’s job approval rating among national adults is at 45% in this final pre-election survey. This is higher than the 38% job approval rating George W. Bush had just before the 2006 midterm elections, lower than Bush’s 63% approval before the 2002 midterms and Bill Clinton’s 66% approval before the 1998 midterms, and about the same as the 46% Clinton had before the 1994 midterms. Presidents whose approval ratings have been below 50% have suffered an average loss of 36 House seats in midterm elections since 1946.”

“Twenty-one percent of Americans approve of the job Congress is doing, and 22% of Americans say they are satisfied with the way things are going in the country right now. Both of these measures are essentially tied with or lower than those before any previous midterm elections since Gallup began measuring them systematically.”