US ad industry ratings watchdog the Media Rating Council (MRC) has withdrawn its accreditation for local television ratings in Nielsen's 154 diary-only markets, backdating the withdrawal to 2009.
In the last few years, Nielsen has moved its recruitment process from landline calling to an address-based method, which it says is more accurate, and which the MRC says it supports.
The MRC withdrew the accreditation after it found that Nielsen had not mailed enough of the diaries to households to generate a sufficient sample size.
According to a notice Nielsen sent to its clients yesterday, the firm is expecting to regain the accreditation for the diary-only services soon. Meanwhile it confirms that its local people meter and set-meter/diary local measurement services will continue to be MRC accredited.
'In the transition to address-based sampling, we underestimated our targeted sample size in two of the four measurement periods, but since November 2009 we have consistently delivered on our targets,' Nielsen said in the client communication. 'Because we now have more experience with address-based sampling, we have demonstrated improvement in the delivery of our key quality metrics and met our targets for 2010.'
Web site: www.nielsen.com .
All articles 2006-19 written and edited by Mel Crowther and/or Nick Thomas.