The TV Measurement System

TAM Ireland commissions contractors to provide research services, including the production of audience viewing figures, on its behalf. The audience measurement contract is held by Nielsen. Nielsen Television Audience Measurement have been providing the ratings measurement service in Ireland since 1996.  TAM Ireland adheres to the highest research standards and the rigour with which it undertakes its task provides a gold standard for TV viewing measurement. Unlike some other media TAM Ireland, on behalf of the TV industry, measures both duration of viewing and reach and has a number of metrics associated with these. To read more about those metrics click here. Below are some videos that explain how the TV Measurement system works.

What is the TAM panel and why do we need it?

The system works via a combination of in-home monitoring of TV set use via electronic meters, together with an Establishment Survey (ES) to ensure that the homes being monitored are representative of Irish TV viewing as a whole.

– Behaviour and Attitudes conduct the ES (the largest random probability sampling survey in Ireland) on behalf of TAM Ireland/Nielsen. A total of 9,350 households per annum (across 2 waves) are interviewed about their TV Set and device ownership, reception type, broadband access, along with household make-up, this survey provides us with the TV landscape upon which to base our panel. The ES also provides the data to create the TV Universes as well as being the source for panel recruitment.

-In-home monitoring is done via the Panel. It is made up of 1,090 homes (approx. 2,700 individuals and 1500 sets). There is a meter attached to every TV set in these homes and all sources connected – Virgin/Sky boxes, games consoles, PVRs, DVRs etc. The meter identifies both channels being watched and the devices used to view.

How does TAM know who is watching?

Viewers register every time the TV set is in use. The meter then listens to the audio and converts this into an audio signature – this is stored in the meter. Every night at 3am the meter is accessed and information from the previous day is downloaded (programme audio signatures & data on the individuals who were viewing)

At the reference site every channel is playing continuously all day every day from all different reception platforms. These are converted into an audio digital signature. The data from the reference site is timestamped and signatures collected from the homes are matched to the reference site. Live content is matched first. Then the matching system scans back to up to 7 days post transmission. The matched data is then put through a rigorous quality control process and it is weighted to ensure it is as reflective of the viewing population as possible
The broadcasters send through transmission and commercial logs which identify the specific times that programmes and commercials aired and these are merged with the viewing data to provide programme and commercial audience viewing data


The data is released at 9.30am each morning reporting the previous day’s viewing. TAM Ireland delivers a vast range of programme and spot advertising performance data including overnights, dayparts, programme and commercial information, time lengths, reach, and channel share of viewing. The data plays a vital role in delivering and measuring the success of marketing campaigns for brands and underpins programme development and broadcasting in the Ireland.

You can view our other videos on the TV Measurement System below:

Further Information

This document gives a full explanation of the TAM Ireland Nielsen service in a simplified easy to use format.


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