Check this out. It was always ridiculous but now a left leaning media watchdog has quantified it.
Well, sometimes the contrarian that I am, I have a different view. Rather than the networks being hopelessly biased, I think the numbers generally reflect the play of events during the subject period, although no doubt at the margins there is bias. Specifically, I would expect that given that while Kerry was demolishing his opponents, Bush during the period gave only an average SOU speech, and performed only fair in his interview with Russert, the Kay report came out, the unemployment numbers remained sluggish and the deficit projections ballooned, nothing much positive came out about Iraq (now something has with the place signing off on a draft constitution) and team Bush was keeping its powder dry until Kerry had a lock on the nomination, one would expect Kerry would have a much more favorable press than Bush during the subject period.
It will be interesting to see that stats for the next two months given that Kerry has hit a negative patch: Kerry gave a suck victory speech (too long, too droning, too cliched and too mean spirited), Kerry refused to back off his calling Republicans liars and crooks per an intrusive mike, team Bush has opened up on Kerry, and unsettling stuff is now being released on Kerry in a drip, drip fashion.