Affinity Index
The Affinity Index is a metric that shows how much a specific audience is more inclined to be interested in a product, brand, or content compared to the average audience.
Simply put:
how much a particular group “loves” a product relative to everyone else
How it is calculated
(Audience share within the target segment / Audience share within the total population) × 100
How to interpret
- 100 → interest is at the average level
- Above 100 → the audience is more interested than average
- Below 100 → interest is below average
Example
Among the entire audience, 10% of people are interested in the product;
among the audience aged 18–24, 25% are interested.
👉 Affinity Index = 250
This means the young audience is 2.5 times more interested in the product than the average.
Where it is used
- media planning,
- advertising targeting,
- TV and digital advertising,
- audience analysis,
- marketing research.
Why the Affinity Index is needed
It helps to:
- find the most relevant audience,
- allocate advertising budget more effectively,
- choose platforms and channels,
- improve targeting accuracy.
Usage example
A brand analyzes media and sees that a sports website has a high affinity index for its target audience.
This means it is more profitable to place advertising there.
Difference from reach
- Reach shows the number of people
- Affinity Index shows the quality of the match between the audience and the target group
Key takeaway
The Affinity Index is a metric of how well an audience aligns with a brand or product. The higher the index, the more relevant the audience is for marketing communications.
