Individuals aged 15 or over are classified as Adults within the TAM service

Audience Category

An audience category is a classification of the viewing audience into a specific group. The following audiences are sometimes referred to as main categories – Homes, Individuals, Adults, Men, Women, Children and Housekeepers. Sub-categories are more detailed breakdowns of the main categories – by age groups, social class etc, for example Men 15-24, Adults ABC1

Audience Profile (Audience Composition)

The audience profile shows how a main audience category is divided into its subcategories (such as age, social grade or sex) in percentage terms. For example, if a programme achieves an Adult ABC1 profile of 10%, this means that 10% of adult viewers were ABC1, while the other 90% were C2DE or F1F2 Adults. An audience profile can be compared with the equivalent population profile to produce an index.

Catch up TV

Content delivered by a broadcaster’s on demand player service that has recently been transmitted linearly by that broadcaster.


TAM reports viewing for Children aged 4-14.

Consolidated Audience

The Consolidated audience is the sum of the live and timeshift audiences.


See Reach.

CPT (Cost per thousand)

Cost-Per-Thousand. The cost of 1,000 commercial impacts for a target audience. Cost-Per-Thousand (CPT) is used when purchasing and measuring the efficiency of advertising campaigns.


A daypart is a section of the viewing day, for example All Day (0300-2659) or peak time (1800-2329).


Digital Terrestrial Television. This is a free digital television service received with an aerial. Saorview is the name of the Irish DTT service.

Encrypted Channels

These are channels that require specific decryption or decoding equipment (such as a viewing card) to display them on the TV screen .


Electronic Programme Guide. The EPG is an onscreen listings guide of TV programming and other on demand content and services. EPGs offer a wide range of functions such as browsing, genre or channel search, marking items for recording, parental locks etc.

Establishment Survey

Large-scale market research study which collects demographic and other household data relating to TV ownership and TV viewing. The survey is conducted 2 times a year and is used to derive universe estimates, platform penetration and other variables on which the TAM panel is then controlled. TAM Ireland Establishment Survey respondents also provide the pool of households from which TAM panel homes are recruited.

Free-To-Air Channels

No subscription fee is payable in order to view the channel.

Frequency (Average Frequency)

The (average) number of times a commercial is seen by those within the target audience who see it at all. Average frequency is sometimes referred to as average OTS (see OTS).


Gross Rating Point. Often used as a measure of the overall weight of an advertising campaign. One rating point is numerically equivalent to one per cent of the target audience (see also TVR).

Guest Viewing

Viewing by non panel members within panel homes. Guests are asked to provide details of their sex and age group via the Unitam handset. Regular guests may be allocated their own button on the handset, though their viewing will continue to be treated as guest viewing.


A device similar to a remote control which panel members use to register and deregister their presence in a room where a television set is on.


High Definition Television. A television service with notably higher resolution pixels which delivers a clearer and sharper picture.

Head of Household

The Head of Household is the household member who either owns the property, is responsible for paying the rent, has use of the home as a result of his/her job, or is related to the owner or main tenant (where the owner or main tenant is not a regular member of the household).

Hours/Minutes of Viewing

The amount of television watched by a particular audience category. This is usually expressed as an average over a given time period.

Household Size

The number of individuals who regularly live in the household.


The member of the household who is solely or mainly responsible for the main grocery shop. A housekeeper may be male or female. There is only one housekeeper per household.

Housekeepers with Children

Housekeepers living in a household in which a child (or children) aged 0-14 also lives.


A measure of viewing to commercial spots. One impact is one member of the target audience viewing one 30 second advertising spot. Impacts are also referred to as gross impressions.

When enough impacts are recorded to generate at least 1% of a target audience, then a TVR (rating) is recorded. Commercial impacts show the total number of people in 000’s who have seen one or more spots in a campaign or on a channel. Each time a spot is viewed, it contributes to the total impacts. For example a total of 20 impacts could be achieved in some of the following ways:


TAM Ireland reports audiences for Individuals aged 4+.

Interactive Television

Mixing traditional television with interactive content on digital TV via the ‘red button’. Information can include links to further programmes, interactive games, commercial advertiser content etc.


An index is an conversion figure between the target audience rating and the base audience ratings.

Linear TV

Television service where the viewer has to watch a scheduled TV program at the particular time it’s offered and on the particular TV channel it’s presented on. This is also known as “real-time”. This excludes the use of PVRs, VCRs, players or Video on Demand.

Live Audience

The audience to a minute, commercial, daypart or programme at the time of its actual transmission. Live viewing excludes any viewing that was time-shifted.

Live TV Streaming

Television service where the viewer has to watch a scheduled TV program at the particular time it’s offered using streaming media.

Multi-Channel Home

A home able to receive more than the 4 Irish channels (RTE1,RTE2, TV3, TG4).

Multi-Set Home

A home possessing more than one television in working order.


Opportunity To See ads in a campaign. A commonly used term denoting frequency of media exposure. In television it is synonymous with frequency.

Out-Of-Home viewing

This all viewing that takes place outside the home (eg viewing in a friends house or at a public venue such as pubs, hotels etc). TAM Ireland measures TV viewing only within private domestic households. The only type of out-of-home viewing captured is guest viewing (see Guest Viewing).


The previous day’s viewing figure are released to the industry at 9.30am the next day.


Sample of people used for regular research. The TAM panel consists of 1,050 homes. This his equates to approximately 2,500 panel members aged 4+ whose television viewing is measured and reported every single day.

Pay TV

TV service that requires a viewer to pay a one off or regular subscription fee in order to view.


Pay TV service allowing users to pay for each programme they watch rather than via a monthly fee. For example, box office films may be watched via pay-per-view.


The length of time that a TV needs to be in a particular status (e.g. tuned to a particular channel) before this status is recorded by the meter. This is currently set to 15 seconds for Live viewing.


A term encompassing the various ways in which a home can receive television. For example, digital cable, digital satellite, etc..


Viewing of broadcast material that has been recorded (see also Timeshift Audience).


The daily process whereby viewing data is collected from each panel home. This is done by the means of a telephone call from the central processing base of the data supplier, which downloads (in the early hours of the morning) the meter data from the previous broadcast day. This is done via a modem connection with the central meter data storage unit in the home.


The number of people in the ‘universe’ or ‘target group’.

Position in Break (PIB)

Refers to the running order of a commercial break and where a specific advertisement fell.

Programme Genre

A classification of programmes into particular types (e.g. drama, sport, documentary).


Personal Video Recorder. Digital recorder, e.g. Virgin on Demand, Sky +, and others, that allows a viewer to record programmes from an EPG and pause live TV for later viewing.

Random Probability Sample

Sample designed to strict procedures to ensure that each member of the target audience has a known chance of being selected for interview. TAM Establishment Survey interviewees are selected via random probability sampling.


See TVR.


The net number or percentage of people who have seen a particular piece of broadcast output (e.g. a programme, daypart, channel, TV advertising campaign).

Programme or daypart reach assesses what percentage of the population saw a specified amount of a programme or daypart. It is also used cumulatively to assess the total net percentage that saw a specified amount of a complete series/month of television etc. There are various ways of defining the amount of viewing an individual must have done in order to be counted as having been “reached”. The TAM Ireland definition is for this is 1+ minute.

For TV advertising campaigns, reach (the net percentage of the target audience to have at least one opportunity to see the campaign) is often used in conjunction with frequency (the average number of times the campaign was seen by those within the target audience who were reached) to produce an overall measure of campaign exposure.

What is the difference between reach and a rating? For example, if a programme achieves an average Adult rating of 20 but the programme reach for Adults was 40% then 20% of the Adult universe watched the first half of the programme and a completely different 20% of the Adult population watched the second half of the programme. 40% of Adults watched some part of the programme which is why the reach is 40% but the average rating is only 20

Sample Size

The number of individuals in a sample group.

Share (Share of Viewing)

The percentage of the total viewing audience watching over a given period of time. This can apply to channels, programmes, time periods etc. For example, a share of 58% for Coronation Street would mean that, of all the viewers watching television when Coronation Street was being transmitted, 58% were watching Coronation Street.

TVR and Share are two of the most common figures we examine when looking at programme performance. The easiest way to decipher them is to remember that: TVR is a % of all available audience, whether they are watching or not. Share is a % only of the audience who are watching. The two figures should be looked at in conjunction with each other when deciphering a station or programme performance.

SI Code

Service Information Code. A code broadcast by a channel that uniquely identifies that channel. SI codes are used by the Unitam meter to monitor the channel being viewed on the digital satellite platform.


The simultaneous broadcasting of the same programme on 2 or more different TV channels.

Social Grade

A classification of household social status based on the occupation of the chief income earner which is then applied to all Adults 15+ in the household. TAM Ireland reports the following social grades:







An individual occurrence of a commercial.


Broadcast of channel output on a secondary channel at a fixed time after the original broadcast. The most commonly used time lag is one hour, and such secondary channels are often labelled “+1”.

Timeshift Audience

The playback audience to a video or PVR/DVDR recording of a minute, commercial, daypart or programme. The recording must be played back within 7 days (168 hours) of the original transmission to be counted by TAM Ireland.

Transmission Hours

The length of time that a channel broadcasts in any given day.

Transmission Log

A detailed description of the events (programmes, commercials etc) broadcast each day by a particular channel. The logs are combined with minute-by-minute TAM audience data so that audiences can be reported for particular programmes, commercial breaks or individual commercial spots.

TVR (also known as GRP-Gross Rating Point)

The TVR (Television Rating) is the measure of a programme, daypart, commercial break or advertisement by comparing its audience to the TV population as a whole. One TVR is numerically equivalent to one per cent of a target audience

Commercial campaigns are frequently assessed by adding the TVRs of their individual spots to produce

A TVR or rating as it is commonly called, represents 1% of a target audience watching a programme or ad break at a particular time. For example, if a programme eg Coronation Street achieved a Housekeeper TVR of 20 in multichannel homes this means that, on average during the programme, 20% of all Housekeepers in multichannel homes were watching. A person must be viewing for at least 15 seconds to be considered in the calculation of the rating. Unlike a share figure, a TVR is a % of all available audience, whether they are watching or not.

Uncovered Set Viewing

The situation where a television set is switched on but no-one is present in the room is known as uncovered set viewing.


Nielsen TAM’s meter used for the electronic measurement system which monitors the channel that a TV set is tuned to and the individuals present in the room while the TV set is switched on.


The total population of a particular audience category. TAM universes are based on television homes. For example, the universe for ABC1 Women is the total number of ABC1 Women living within television households in Ireland.


A facility offered by digital television providers where households can access a movie or programme that can be watched at any time.


A panel member (or guest) is defined to be viewing when they are present in a room with a TV set switched on.


Video on Demand – the viewer can watch programming at anytime other than when it’s scheduled by a network – this excludes PVR viewing. E.g. via a channel’s player.


Viewing-On-Same-Day-As-Live. Time-shifted viewing that has been viewed on the same day as the original broadcast is included in the overnight file which is released at 9.30am the following day (see Overnights).

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