“In the weeks leading up to this prelude to the upfront advertising marketplace, the Media Rating Council quietly met, reviewed a crucial audit of Nielsen’s so-called C3 ratings system, and opted to withhold accreditation for what will be the currency for billions of dollars in TV advertising buys.”

Confused? Allow us to explain. You know those upfront presentations all the networks are hosting to solicit ad buys for the upcoming television season? Those billion dollar deals are based on Nielsen data that hasn’t passed muster for the second year in a row.

And then it gets worse.

“Details of the audit, the review, and the reasons for withholding accreditation have not been disclosed. What is known is that the audit covered the TV commercial data used by Nielsen to compute the average minute ratings that have become the trading currency of the national TV advertising marketplace, and that Nielsen plans to come back to the MRC in the next several weeks with a plan for addressing the problems raised by the audit.

“Even if Nielsen manages to assuage the MRC committee’s concerns about the validity of the TV commercial data, the Nielsen ratings face a second hurdle: a separate audit of the process Nielsen uses to process the TV commercial data with its TV audience estimates into C3 ratings.

“The bottom line, say executives familiar with the process, is that it is unlikely that the new TV ratings system will be accredited by the start of upfront negotiations, and possibly not even by the start of the new TV season next fall.” [MP]

All that said, let’s not pretend it’s going to matter. At this point, this is the only “reliable” data that ad buyers and networks have to go off of, and they’re more than happy to sweep any liabilities under the rug.

And while the competition continue ramping up its game to offer realistic marketplace alternatives, Nielsen’s been smart in keeping them quiet. By buying them.