Frequency Capping: Best Practices 2019 Guide (GDPR)

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Frequency Capping is a method in online advertising to limit the number of times a banner ad is shown to a visitor. Some ad serving platforms may also refer to this as impression capping. One of the best arguments to set such a cap is to minimize banner blindness and to increase the CTR and ROI of your campaign. In one sentence: frequency capping allows you to reduce campaign costs while increasing the campaign's unique reach. This is once more an excellent example why you need an ad server.

Frequency Caps: Best Practices

Setting a frequency cap for an online advertising campaign is almost always recommended in most situations unless you're running remarketing or brand awareness campaigns and your CTR is of less importance. If you're a publisher, limiting the exposure rate is equally recommended to avoid bothering your visitors with the same ads and to help to increase your advertiser's ROI. The optimal number of impressions per visitor is hard to estimate and may depend on the type of campaign, your objective and the available inventory. We believe it's best practice to:

  • Set an initial cap between 5-7 impressions per day
  • Gradually increase this number while measuring performance based on your KPI (usually CTR)
  • Enable Lazy-Loading of your ads for better viewability and increased CTR

Fine-tuning your cap to find an optimum might sometimes be easier said than done: you don't want your visitors to be bombarded with the same ad over and over again, while at the same time you want to make sure your audience gets your message. You can consider to set up a few tests to measure your daily unique reach before and after changing your impression cap. Your strategy could look like this:

Frequency Capping Strategy - Best Practices

Lazy-Loading Ads: Why does this matter?

Being an advertiser, you want your audience to actually see your display ad in order to spread your message. Ads which are loaded below the fold remain unseen if the visitor never scrolls down the page. That's a waste of money and resources. Lazy-loading makes sure the ads are loaded as soon as the ad unit is scrolled into view. That means the ad is loaded and displayed right there in front of the eyes of the visitor. If you set an impression cap of let's say 7 impressions a day, you may assume here that the visitor has actually seen the ad 7 times. Without lazy-loading, this may likely not be the case. If you're A/B testing your campaigns to find the optimal frequency cap, you may want to enable lazy-loading as well.

Multiple Caps: A clever strategy to distribute ads

A common marketing strategy to distribute media exposure over the day is to set multiple frequency caps. The ad serving engines evaluate all rules, and makes the ad ineligible for display if either rule is true. This can be a clever method to make sure that visitors who stay on the page for a long time are remembered about your message, while not being overwhelmed with the same ad on each page load. For example, you may want to configure your campaign to have the following caps:
  • 5 impressions per hour
  • 25 impressions per day

If you're taking this route, you may also want to prevent the same ad showing twice on a page (see the Settings page in AdGlare).

Frequency Capping under the GDPR (Important)

GDPR Compliant Ad Server Traditionally, frequency caps work by generating a unique ID which is stored in a third-party cookie, and then sending that ID along with every ad request. The ad server keeps an internal log and matches the unique ID with the number of times a certain campaign was shown. This practice however will be illegal under the GDPR (as per May 2018), and may result in heavy fines for publishers if the ad server vendor uses this technique.

AdGlare's method does not use personal identifiers, does not use IP addresses and does not store cookies whatsoever. Instead, all capping data is stored in the visitor's browser, while the campaign ID is used as an identifier. By not processing or storing personal data, AdGlare's approach to frequency capping is GDPR compliant.

What's the bottom line?

Frequency caps comes with great advantages for both advertisers and publishers. You'll likely benefit from capped campaigns because it...
improves CTR
increases the number of conversions (due to a higher unique reach)
reduces campaign costs or increases ROI
minimizes banner blindness
avoids visitors being overwhelmed with the same ad over and over again
can be used without personal data, if you use a GDPR Compliant Ad Server

How to set up a Frequency Cap in AdGlare

To set up Frequency Caps, browse to the page Campaigns and open your campaign. On the Settings tab, you'll find the option to limit campaign exposure. See the screenshot below. AdGlare does not use PII or other personal identifiers for this to work.

Setting Frequency Caps in AdGlare

Campaign Throttling

Impressions of all creatives and all visitors are counted toward the campaign's frequency cap settings. Here's an example:
  1. You've set a campaign cap of 10,000 impressions per hour on a campaign with creatives A and B.
  2. Creative A has got 3,000 impressions this hour and creative B got 7,000 impressions.
  3. The campaign cap will thus be applied automatically, and ad serving resumes when the next hour starts.

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