I notice on P.ie and all over the media people use the term "statistical dead heat".

So if a poll has a margin of error of say +/- 4% and Candidate A has 45% and Candidate B has 48% the commentators say the race is a "statistical dead heat" ... what on earth do they mean ? That race is not a dead heat:

International Statistical Institute, 53rd Session 2001: Douglas Lonnstrom

With the worldwide proliferation of political polling, especially in the United States, the mass

media has coined the term ‘statistical dead heat’. The intended meaning is to call the race a tie if the

two candidates have percentages that fall within the sampling error. For example, if we have a sample

size of 600 the sampling error is +/- 4 percentage points. Therefore, if candidate A has 45% of the vote

and candidate B has 41%, the media is calling it even. I say this is not so. In fact, it is my contention

the media makes four errors when they use the term ‘statistical dead heat’. There certainly can be a tie

if each candidate has the same percentage, i.e. 45% to 45%. In any other case the candidate with the

higher vote is more likely to be ahead, even if the difference is only one percentage point.

ERROR 1 – Let’s start with the extreme case: A has 45% and B 41%, this is within the sampling

error margin for a sample of 600. Using the recognized statistical calculation called ‘power of the test’

(Berenson, 1996), the probability that B is tied with or ahead of A is 2%. Hence, there is a 98%

probability A is in the lead. Now, test the least extreme situation. Even though A is ahead 45% to 41%

assume the tie occurs at 43%. The ‘power of the test’ still shows A is the likely winner, although the

probability drops to 84%. A third scenario would be to have the poll show only a one point spread,

45% to 44%. Even then the ‘power of the test’ produces a probability of 69% that A is the leader. In

short, you would rather be ahead in the poll, no matter the margin, then behind.

ERROR 2 –...I think that this is a stunning indictment of the chattering classes: why are they using terms that make no sense ?Blog

And just in case Salon isn't convincing for you, here's the National Council on Public 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.

Also see Illustrative table

It appears to show a fundamental misunderstanding of probability ... why do we even bother with opinion polls ?

cYp