Nielsen ratings glitch may give wrong DVR viewing data


Nielsen has begun informing clients 9/21 about a software problem that has been generating incorrect data for most of this year for GRPs, reach and frequency estimates. Earlier this year Nielsen changed the way it handled DVR viewing so that if a show were watched multiple times on DVR, those views would be counted and included in GRP reports. Nielsen says those DVR viewing numbers may have been inflated due to a processing glitch that delivered “incorrect data for time shifted streams.”

According to MediaPost, which originally reported the client letter’s contents, the snafu will likely affect TV ad plans made in the uprfront—specifically the possibility of millions of dollars in makegoods from the networks back to advertisers over time shifted viewing estimates.

However, Nielsen SVP/Global Communications Matt Anchin told RBR-TVBR this will not affect upfront deals at all, as C3 ratings–the currency for TV buying–were not affected: “Yesterday Nielsen informed clients that as a result of changes made earlier in the year for the measurement of multiple viewing of programs in TV homes, the reporting of Program Viewing Frequency in the NPower tool is overstated, affecting the NPower-reported Program GRP.  There is no impact to C3 Commercial Data, Ratings and Projections, electronic data files used by other processors, or to Reach or any other NPower-reported data.”

The problem began when Nielsen implemented its NPower platform for calculating average audience estimates in its main TV ratings processing system beginning in February. It appears to have been delivering incorrect data for time-shifted viewing streams since 1/31/11. NPower is what agencies and advertisers use to get their reach and frequency and GRP estimates for their ad buys and guarantees, as well as post buy analyses of performance. 
NPower is only one metric that’s reported out by a tool, and because it is used to calculate a GRP, that’s the only connection to GRPs. Again, C3 is not affected.

Nielsen will be changing its methodology in NPower and is currently working with clients on that matter.

Nielsen said it became aware of the problem when clients “inquired about elevated average frequency levels” for the time-shifted viewing data. The glitch may have over-inflated TV audience estimates, Nielsen said in the letter.

Nielsen also has a similar problem with its Net Ratings service late last year. The company was undercounting time spent traffic to websites for three months due to a flaw in its system. The glitch especially affected social media site numbers.