What is a Frequency Cap?
A frequency cap is a limit to the number of times each user sees an ad, generally expressed as a per-day allotment (3/24 means 3 times per 24 hours per user). It is literally a cap on frequency.
3/24 is generally the best frequency cap for some unfathomable sociological reason, as on average more users will click on your ad if they see it 3 times per day. This is just an average of course, and different frequency caps will be appropriate for different ads on different networks.
Frequency Cap Advice for Site Owners
You should try and add frequency caps to campaigns you run. If you keep showing the same ad to the same user repeatedly, they will probably only interact with it once at most. This will make your advertisers feel like they have wasted their money, and they are less likely to come back for more.
Therefore, you want to spread your ads over many users, and keep showing them daily to everyone so as to maximise exposure. This is the best way to make users more engaged with your ads and therefore make the most money.
Therefore, always frequency cap CPC campaigns at 1/24, and CPM campaigns at 3/24 if you can. Also, cap invasive ads (like video ads and overlays) at 1/24 to make sure you don’t annoy your users. Let CPA campaigns run uncapped if allowed, as you want to drop cookies on as many users as possible.
Frequency capping has some technical limitations. As well as the limitations of cookies in general, it can be challenging for multi-device frequency capping to be effective. If a user is logged in on a site or service, it can be possible but it depends on the individual technical implementation.
Frequency Cap Advice for Ad Buyers
When you are advertising on a CPM basis, to ensure that you hit as many unique users as possible, you should ask for a frequency cap, preferably of 3/24.
If you are advertising on a CPC basis, it is still a good idea to ask for a frequency cap, this time of 1/24. It is probably unnecessary, however, as most ad networks will cap CPC campaigns as a matter of course. This is because they want to be as efficient as possible when serving a CPC campaign to make more money.
Basically, a CPM campaign earns ad networks money whether or not people click on it. This means they might as well show those ads all the time. CPC ads however only make ad networks money when someone clicks on them. This means they’ll try only to show them when the likelihood of a click is high.
A good advertising company will experiment with a frequency cap for your ad campaign until they find what is best for you. Unfortunately in most cases, it will be largely an ignored setting in an ad server, and if the website you are advertising on is in need of space, they will not hesitate to remove it altogether.
Therefore check your reports, and always make sure a frequency cap you asked for has been applied.
To roughly work out the frequency your ads have been shown at, you can use the frequency formula:
Frequency = Impressions ÷ Users (per timeframe measured)
Example: Thirty impressions served to three unique users in a 24 hour period would be expressed as 10/24 (as each user saw 10 impressions).
Other names for Frequency Cap (synonyms)
Ad Frequency Cap
Not to be confused with