Nielsen botches Network Ratings Attribution

In response to recent ratings irregularities, Nielsen conducted an extensive internal investigation of their systems and processes and uncovered a technical error that impacts national network television ratings over several months.

The technical error was introduced on March 2, 2014, and was generally imperceptible until we saw high viewing levels associated with fall season premiere week. As a result, small amounts of viewing for some national broadcast networks and syndicators were misattributed. Cable networks and local TV ratings were not affected by this error.

A software fix to correct the problem was deployed on Oct. 9, 2014, meaning that all data being released today and going forward is correct.

In addition,

    •    All of the commercial data—including C3—for the current TV season, which will begin releasing this weekend, will be correct.
    •    All previously released data since September 22nd will be reprocessed and reissued by Oct. 17, 2014.
    •    They will also reprocess all of the impacted data going back to Aug. 18, 2014, when the first new season broadcast network program aired. This data will be reissued by Oct. 31, 2014.
    •    Nielsen is also conducting an impact analysis to determine whether additional weeks should be reprocessed.

This issue has to do with difficult-to-attribute content called “all other tuning with code” (AOT with code). This data represents between 0.1% and 0.25% of all viewing minutes that they credit nationally. In the vast majority of cases, the impact is small; in a handful of cases, the impact is more significant.

As part of our investigation, they have also determined that there are no issues with the National People Meter, our data collection process, the panel, the TV audience measurement methodology or the total TV viewership data produced during this affected period.