Nielsen says glitch caused second erroneous website visitor report

The Nielsen Company said November 17 that it underreported the audiences of the top 1,000 websites by an average of 5% in September. It is the second time this month that Nielsen has identified erroneous website visitor numbers.

However, the research, ratings and data provider said it is working to deliver accurate audience measurement statistics for next month.

“We are on schedule for December,” said a Nielsen spokesperson. The spokesperson confirmed that the company sent a letter to clients this week saying the error mainly affected online audience estimates for NetView, its Internet audience measurement service.

The glitch also affected VideoCensus, Nielsen's online video measurement service, but to a lesser extent. The spokesperson also said, declining specifics, that Nielsen is working on a technical solution to the problem. The company will delay the delivery of this month's data until the end of December to ensure it is distributing accurate numbers, the spokesperson confirmed.

Nielsen said November 5 that it was reviewing its processes with the nonprofit Media Rating Council after erroneously reporting a 22% year-over-year decline in consumers' time spent on some websites.