There was no reason to suspect that the midterms would be any different than prior elections. The pundits typical reaction promotes the conventional wisdom that it was a GOP blowout of epic proportions - even bigger than 1994. The party in power nearly always loses seats in the midterms. But the true number is unknown. The unconventional wisdom is that in every election the Democrats do significantly better than the recorded vote indicates. The 2010 midterms were no exception.
This analysis utilizes final likely and registered state and national pre-election polls along with preliminary and final exit polls. The 2010 Election Forecast Model predicted that the final LV pre-election would closely match the recorded vote and they did. Final exit polls are always forced to match the recorded vote (Table 3 lists late adjustments made to the exit polls without any additional respondents). On the other hand, pre-election RV polls have closely matched the unadjusted exit polls. At least they did until 2008, when the National Election Pool (the consortium of six mainstream media giants which pay the exit pollsters) decided that it was bad for business to release the pristine data.
National (Generic) Exit Poll vs. Pre-election polls
As expected, the final 2010 National Exit Poll margin discrepancy from the average of 30 pre-election generic LV polls was a near-perfect -0.62.
The returning voter mix was set to the 2008 recorded vote. The discrepancy from the 19 pre-election RV poll average was an even lower 0.07%.
State exit polls vs. Pre-election polls
The final state exit poll (i.e. recorded vote) discrepancy from the average LV poll was 1.52%.
The state exit poll returning voter mix was set to the 2008 recorded vote. The discrepancy from the RV poll average was an even lower 0.83%.
As usual, the pundits are quoting the final exit polls as gospel. They warn Obama that he must move to the center as if he has been part of the "professional left" all along. They never question the official results. That's why they're pundits: they know that they are paid to present the recorded vote as if it represented the will of the voters. So they avoid the subject of: systemic election fraud - otherwise they might find themselves suspended indefinitely at best.