• by Joe Mandese  @mp_joemandese, January 9, 2008

The New England Patriots may be 16 and O for the NFL season, but they appear to be 13 and 3, according to the Nielsen season. For the second time in weeks, Nielsen has disclosed a glitch with its supposedly fool-proof A/P (active/passive) coding system, this time causing two TV stations to understate ratings for the coverage of several New England Patriots games.

"In evaluating ratings for the December 3, 2007, October 1, 2007 and October 30, 2006 New England Patriots games carried on WCVB, WMUR and ESPN Network, determined that a technical problem existed with the stations' encoding equipment," Nielsen said in a notice issued to clients on Tuesday.

Nielsen said the problem occurred because "audio codes were not present on the station feeds distributed to cable and satellite providers."

It was the second time since late December that Nielsen disclosed a problem with its coding system, which was designed to be purposely redundant with both active and passive coding to ensure such problems could not occur in the ratings process. Nielsen has said such glitches are "rare," but the new disclosure throws a yellow flag down on the playing field, and will require Nielsen to take steps to ensure it doesn't happen more often.

Nielsen said it would contact TV stations within the next few days detailing steps they can take to "these and other types of encoding related issues that may not be currently identified."

Nielsen said the issue disclosed Tuesday was "unique to these games due to their being simulcast, and the fact that the ESPN network feed was audio encoded with the ESPN Network final distributor code" and that there were instances where credit was given to the ESPN Network when a home was actually tuning to WCVB or WMUR, resulting in an understatement for the stations' ratings and an overstatement in ESPN's.

On Dec. 20, 2007, Nielsen disclosed a failure of both the active and the passive components of its coding system used to measure WKRN-TV, the ABC affiliate in Nashville, Tenn.

Nielsen did not explain to clients specifically what happened, but it acknowledged that the failure involved both the "station's encoding equipment" (the active portion of its system), as well as its Nielsen's passive monitoring of the station's signal.

Nielsen said the glitch happened twice: Once between Nov. 5 and Nov 7; as well as between July 10 and July 14. As a result, Nielsen said WKRN would be permitted to "retitle" its programming during those periods.