How do they measure TV audiences?
Nielsen TAM gather information about Irish television viewing from a nationally representative panel of 1,050 homes. This equates to approximately 2,500 panel members every day. They measure viewing on every set within each panel home. Since September 2010, Nielsen TAM have also been measuring time-shifted viewing (TSV). Time-shifted viewing that takes place within 7 days of the original broadcast is included in audience ratings.
The Establishment Survey
A large household survey called the Establishment Survey is conducted 3 times a year to establish the size and nature of the television population in Ireland. The fieldwork for the survey is carried out by Behaviour & Attitudes, Ireland's largest independent market research company, on behalf of Nielsen TAM. The survey is one of the largest face-to-face random probablility surveys carried out in Ireland. The sample size exceeds 2450 interviews per wave (7350 per annum) with fieldwork conducted on a continous basis throughout the year.
The Establishment Survey is a household-based survey. The questions are asked of the main grocery shopper in each household, i.e. the Housekeeper, but they are encouraged to get help answering from other members of the household.
Data from the Central Statistics Office is used to weight the results of the Establishment Survey to ensure that the panel is representative of the television household population in terms of age, region and sex. AIMRO data is used to weight the responses by social class.
Information derived from the Establishment Survey includes:
- TV Universes
- Reception Type
- Channels Received
- DVD Penetration Levels
- PVR Penetration Levels
- Number of TV Sets per Household
- Games Console Penetration Levels
Many other details that relate to, or may affect TV viewership, are also collected.
Panel controls and universes are derived from the weighted data. These are updated 3 times a year to ensure that the service keeps pace with consumer and population developments.
The panel is designed to be representative of the television population as defined by the Establishment Survey. Households meeting the demographic requirements are invited to join the Nielsen viewing panel. In September 2009, there were 670 homes on the panel. Under the terms of the new contract, this rose to 800 homes in September 2010, 920 in 2011 and 1,050 in 2012. There are currently 1,050 homes on the panel, which is one of the largest per-capita panels in Europe and one of the most representative.