Measurement Foundations: Reach and Frequency

What are Reach & Frequency?

When an advertiser wants to know how many different people will see an advertisement and how often, the metrics used are reach and frequency.

Reach measures how many different people see an advertisement. It counts each person only once, no matter how many times they see a unit during the reported period. Therefore, total reach can never be more than 100%

Frequency measures the average number of times the target audience will see that advertisement in a specific time period.

Relating Reach & Frequency to GRPs/TRPs

Though the formula is relatively simple, it is important to understand that reach and frequency occur at different rates in an inverse relationship, and are a product of GRPs. Within a given number of GRPs, as one goes up, the other goes down. 

Should I Optimize Reach or Frequency?

In a perfect world, both reach and frequency would be maximized. However, most advertisers don't have the budget to emphasize both; therefore, a decision must be made in favor of one or the other.

THINGS TO REMEMBER:

• Reach measures how many different people see an advertisement. It does not include duplication and therefore cannot be added like Impressions and GRPs.
• Frequency measures the average number of times an advertisement is seen.

If you have any questions or comments, please reach out to geekout@geopath.org!