That’s a good question — one Nielsen can definitely answer, using half-hour, quarter-hour,or even minute-by-minute viewership of both candidates’ speeches. Unfortunately, that’s beyond the scope of this blog — at least for now!

-Nielsen Communications

Nielsen’s audience estimate is for a national audience that credits viewing to all the national originators for which Nielsen reports audiences. Our production process takes into account those local markets where network programs might be pre-empted. Also, some of the cable networks included in the audience estimate might not be available in all local markets, but that is another part of the process that Nielsen tracks when producing audience estimates.

-Nielsen Communications

In theory, Nielsen’s historical TV audience data could confirm or debunk your thesis. Unfortunately that would require extensive research into the average numbers of people and households watching TV before and after Labor Day – and that’s way beyond the scope of this blog!

Please also note that Nielsen’s universe estimate changed as of September 1, making the U.S. TV audience as a whole a “larger sandbox,” as the Washington Post called it.

-Nielsen Communications

You are correct in noting that PBS and C-SPAN are not included in Nielsen’s ratings for the final night of the Republican National Convention.

Just as PBS does not distribute programs in the same way that broadcast networks do, Nielsen does not provide PBS with ratings in the same way. Typically, PBS identifies those programs for which it wants national audience estimates and provides Nielsen with a line-up of stations around the country that air that program along with days and dates the shows air. Nielsen then verifies that the stations carried the show using electronic verification and produces audience estimates. This is a more time-consuming method than is used with commercial broadcast and cable networks — and is only done for those national programs that PBS selects. As such, Nielsen did not include PBS audiences in its overall measurement of convention TV viewership.

C-SPAN is not included because Nielsen does not measure and report C-SPANs’ audiences. Many cable networks choose not to have Nielsen measurement for a variety of reasons specific to the network. For example, the home shopping networks also do not subscribe to Nielsen.

In answer to your final question — the NFL’s kick-off game between the New York Giants and the Washington Redskins ended before Senator McCain’s acceptance speech began.

-Nielsen Communications

Although we don’t go into such statistical depth on our blog, detailed tables on standard error, etc. are available to our clients.

-Nielsen Communications

I don’t think these ratings have any bearing on which candidate Americans are more interested in or likely to vote for!

And as someone else mentioned, one of the major networks was actually showing a football game during McCain’s speech, so are those viewers counted?