CRE Finds Widening Error in TV Diary Samples

In the US, the Nielsen-sponsored Council for Research Excellence says its recent study findings show random error in Nielsen diaries continues to grow, with the great majority of local broadcast and cable ratings falling outside the traditional 10% benchmark error range.

The CRE is an independent research group created (in 2005), and funded by Nielsen. The body is dedicated to advancing the knowledge and practice of audience measurement methodology, and its members represent advertising agencies, media-buying firms, media companies, advertisers and industry organizations.

Following the latest study, the CRE says the current relative error for total-day in all diary-only household ratings for all TV stations falls within the 10%-benchmark range just 11.3% of the time. Primetime ratings fall within the range 26% of the time and those for weekday evenings and late newscasts 18.1% and 20.7% of the time, respectively. Where sample sizes are smaller, for example because age ranges are selected or in smaller markets, the error increases.

The study was based on eleven years' worth of information provided by Nielsen, covering 31 diary markets, along with posted advertising schedules; and was enhanced with a series of interviews with local-television advertising buyers and sellers, and Nielsen experts.

Billy McDowell (pictured), VP Research at Raycom Media and Chair of the CRE's Local Measurement Committee, comments: 'Our goal was to examine potential instability in ratings as evidenced by relative error. In using TV diary ratings information - still used in 30% of all television households - both buyers and sellers are challenged to predict ratings performance accurately. Diaries do provide an economical way of understanding the 'uniqueness' of each local market, but they are becoming less precise.' He concludes: 'There are no 'quick fixes' for the diary methodology, although Nielsen continues to work on improvements such as the electronic diary and the newer 'code reader.' In the meantime, the statistical limitations should be realized when conducting business using these data.'

Web site: www.researchexcellence.com .

All articles 2006-23 written and edited by Mel Crowther and/or Nick Thomas, 2024- by Nick Thomas, unless otherwise stated.