Where the TVNZ data comes from
Every number in the dashboard traces back to one of two sources, and knowing which one explains most of the questions people ask about it — why a number has changed when you look at it again a few days later, why linear and digital impressions are not quite the same thing, and why the last few days of delivery data should be read with care.
| Digital (TVNZ+) | Linear (broadcast TV) | |
|---|---|---|
| Source | Google Ad Manager (GAM) delivery records | Nielsen audience ratings and the broadcast spot schedule |
| How an impression is counted | Directly, one per ad served | Estimated: the audience rating for the 15-minute slot the spot aired in, applied to the audience universe |
| Does it change later? | No | Yes, when consolidated ratings replace overnight ratings |
Digital
Digital delivery is counted directly from the ad-serving records GAM provides and is processed as part of the daily TVNZ pipeline. An impression is one ad served to one profile; the data, once processed, does not change.
Linear
Broadcast delivery is not observed ad by ad. Nielsen provides audience ratings in 15-minute intervals for each audience group, and tvbeat combines those ratings with the times each spot went to air to estimate the audience for every spot. That estimate is a linear impression — and on linear an impression and an impact are the same figure, as Metrics explains.
Overnight and consolidated ratings
Nielsen publishes two versions of the same audience:
- Overnight ratings arrive shortly after a programme airs. They are preliminary, and may be revised.
- Consolidated ratings are the final, verified figures, and the official ones.
The dashboard uses consolidated ratings wherever they exist and overnight ratings until they do. So the audience for a recent spot can change when its consolidated figures land, and linear impressions for the latest period are preliminary until then.
Reading recent linear figures
Treat the newest linear results as provisional. Once consolidated ratings for a period have been received and processed, its linear impressions are the final available measurement.
When the data is updated
TVNZ data is processed daily, and the dashboard holds both the history and each day's new data. Source data can arrive late or be corrected after it first arrives, so the most recent days can still change as further processing runs. Read the last few days as preliminary, on digital as well as linear.
Filters and the default view
The figures you see depend on the filters that have been applied. TVNZ has global filters set up to give a consistent default view: business rules, pre-agreed with TVNZ stakeholders, that decide which records are included before you choose anything. They can be changed at any time on the authorisation of a TVNZ representative, and the same agreement decides which metrics and dimension values the dashboard exposes. From that default you narrow with the dashboard's dimensions: campaign, advertiser, channel, programme, agency, genre and the rest. Two people looking at different totals are usually looking through different filters; see Filter rules for how a group's filters are set.
What is coming
Linear reach is not yet calculated and shows as 0; it depends on Nielsen reach data that is still being arranged. Cross-platform reach, a combined view of unique reach across digital and linear including the overlap between them, is planned for Phase 3.
Related
- Metrics — every metric, defined, with the calculations behind them
- Dimensions — every dimension you can filter and break down by