Edit to put conclusion in top post and a bit more here..
This next bit should make for lively discussion around the election
forum...
The refusal by Edison/Mitofsky to permit independent analysis of their trove of data has deepened public concern. The shoddy and inadequate analysis (claiming, for example, that linear correlation
analysis, or a 56%-to-50% response bias, is sufficient to support the E/M hypothesis) that has been released to the public has deepened the uncertainty about what happened in the 2004 elections.
The Mitofsky/Liddle pervasive mean bias conjecture is unsupported by and inconsistent with the publicly available data.
Spin and obfuscation have spread the myth that the "exit polls are unreliable". The support of the media for the pollsters' exit poll response bias hypothesis as an explanation of the discrepancies
between the exit polls and the election results in the presidential election, without any serious evidence, has been a travesty.
http://electionarchive.org/ucvAnalysis/US/Presidential-Election-2004.pdf