"Statistical dead heat"

CNN:

With the dust having finally settled after the prolonged Democratic presidential primary, a new CNN/Opinion Research Corporation poll shows Sens. John McCain and Barack Obama locked in a statistical dead heat in the race for the White House.

With just over four months remaining until voters weigh in at the polls, the new survey out Tuesday indicates Obama holds a narrow 5-point advantage among registered voters nationwide over the Arizona senator, 50 percent to 45 percent. That represents little change from a similar poll one month ago, when the presumptive Democratic presidential nominee held a 46-43 percent edge over McCain.

Nate links us to a primer by the National Council on Public Polls that tells us how media should report on polls:

Certainly, if the gap between the two candidates is less than the sampling error margin, you should not say that one candidate is ahead of the other. You can say the race is "close," the race is "roughly even," or there is "little difference between the candidates." But it should not be called a "dead heat" unless the candidates are tied with the same percentages. And it certainly is not a “statistical tie” unless both candidates have the same exact percentages [...]

When the gap between the two candidates is more than the error margin but less than twice the error margin, you should say that Candidate A "is ahead," "has an advantage" or "holds an edge." The story should mention that there is a small possibility that Candidate B is ahead of Candidate A.

Obama is ahead in this poll. There is a chance the poll is wrong, given the 3.5% margin of error, but when the poll says Obama is ahead by five points, it means something, and it's not the same as if the poll was 45-45.

Furthermore, the Pollster.com national poll composite currently has Obama leading 48.5 - 43.9, just shy of the 5-point margin in the latest CNN poll. In other words, chances are that its results are not an outlier.

Of course, CNN desperately wants their dead heat. It's good for ratings.