Reach
In practice, for a UK buyer
The paragraph above is the neutral answer. This is the part a vendor glossary leaves out.
Reach across channels is almost always modelled rather than counted, because no single seller can see the others. AdBuyMCP models it with Sainsbury deduplication against the persona universe and labels the result modelled wherever it appears — the label is a permanent property of the field rather than a footnote. The naive alternative, adding each channel's reach together, is the single most common inflated number in a media report.
What this one connects to
Most confusion in media buying comes from two adjacent terms being used interchangeably, so these are the neighbours worth reading next.
Deduplication
Removing the double-counting that occurs when the same person is reached by more than one channel or placement in a campaign, so that combined reach reflects distinct people rather than the sum of each channel's separate count.
Frequency capping
Limiting how many times one person or household sees the same advert within a given period, to control wear-out and wasted impressions. It is set per campaign, per channel or — rarely — across channels, and that granularity is what decides whether the cap means anything.
Share of voice
A brand's advertising presence expressed as a proportion of all advertising in its category, in a given market and period. Used as a planning benchmark on the argument that share of voice above share of market tends to precede growth.
Modelled
A number produced by a formula or an estimate rather than counted directly from observed events, and therefore carrying assumptions with it. Deduplicated reach and frequency across channels are the common examples, since no single seller can observe the others.
More on targeting and identity
How an audience is described to a seller, and how much of the description survives. Most of the honest difficulty in media buying lives here.
45 minutes. Bring a real brief and we compile it live. You describe one audience and watch it compile into seven targeting specifications, each with the score for how much of the definition survived.
Talk it through