Zogby has low credibility. You really cannot accept as fact any statement from Zogby.
They kicked me off the Zogby polling...
;-)
2006 Zogby Results, Senate Races
1. Missouri (McCaskill v. Talent)
Final Zogby Poll: McCaskill 46, Talent 43 (McCaskill +3).
Actual Result: McCaskill 50, Talent 47 (McCaskill +3)
2. Virgina (Webb v. Allen)
Final Zogby Poll: Webb 45, Allen 44 (Webb +1)
Actual Result: Webb 50, Allen 49 (Webb +1)
3. Tennessee (Corker v. Ford)
Final Zogby Poll: Corker 53, Ford 43 (Corker+10)
Actual Result: Corker 51, Ford 48 (Corker +3)
In 2006, Zogby got all the outcomes right and got the spreads right as well, except in Tennessee where he significantly overstated Republican performance. He did screw up in 2004, but he was very good in '02 and '06.
Zogby predicted every 2006 Senate race correctly.