Viewership measurement for broadcast — shows percentage of target audience watching. Determines ad rates and greenlights.
Ratings determine whether a series lives or dies on television and increasingly with streaming services. The share of viewers using a particular time slot – measured in percentage points of the total population or the available target audience – is the central business model for traditional broadcasters. No ratings, no advertising budget; no advertising budget, no next season.
On set, the pressure of ratings is usually felt indirectly: the producer gets nervous if test screenings go poorly. The broadcaster suddenly demands more action in the third act because similar shows performed better in the 14-49 demographic. A rating of 15 percent in this age group is now a respectable result for a primetime series – 15 years ago, one would have complained about it. The fragmentation of the audience in the streaming era is real. Netflix is not interested in traditional ratings, but in Completion Rate and account activation, but the principle remains: numbers decide survival.
Practically relevant details: In Germany, ratings are collected by the AGF Videoforschung (formerly: GfK) using a panel model – a representative sample of around 5,000 households with electronic measurement devices. This is relatively robust, but not error-free. A rating can be off by ±2 percentage points. The broadcast date, day of the week, competing programming, and even the weather massively influence the result. A Thursday at 8:15 PM has different chances than a Saturday at 11:30 PM – a production's budget must anticipate this.
Specifically for the daily work on set, this means: The planning department calculates with target ratings, not ideals. The editor knows that a scene that lasts eight minutes in the rough cut might be too long if the broadcaster demands pacing for higher retention in the target group. The Slot Quality – primetime vs. daytime – defines how ambitious the rating can be. A series at 2:00 PM on Sat.1 with 8 percent is more successful than one at 10:00 PM with the same rating. So, ratings are not to be read absolutely, but context-dependently – and that is precisely what makes them both a tool and a constraint for producers.