Viewability best practices

Get the best possible viewability results by following these best practices for your website and content.

Web design and layout

Page length

Short form content yields higher viewability, therefore set pages to have only one fold. If you must have longer form content, activate infinite scroll.

Learn how to place tags on a page with infinite scroll

Latency

Latency is caused by a number of issues, one of which is passbacks. The reduction of latency from passbacks increases viewability. The elimination of passbacks improves viewability metrics.

This can drastically increase the viewability of your video inventory, because when a video loads faster, viewers are less likely to leave before the video starts playing.

• Optimize for speed and responsiveness: Ads load faster and have better viewability rates on speedy and responsive sites and apps. This can be particularly important in emerging markets with slower connection speeds.
• Explore lazy loading for article pages, which means waiting to load the video and serve an ad until someone scrolls down further on your page. Infinite scroll, a form of lazy loading, is when the browser scroll bar keeps scrolling but never reaches the bottom of the page, which causes the page to grow with additional content. Lazy loading can increase the speed of your site, reduce load time and latency, and improve viewability of your video ads.
• Consider setting a data-loading-strategy attribute on amp-ad tag. By default, <amp-ad> renders ad slots from 3 to 12 viewports away when AMP scheduler is idle. While this increases impressions, it might decrease viewability. Setting the data-loading-strategy can improve viewability by rendering ads when the user scrolls down closer to the ad slot. At the same time, it decreases impressions and revenue.
• Use an analytics solution like App Speed reports to measure how fast app pages are loading and how long different requests take to load in your app.
• Use Google's AMP format to ensure your website is fast and user-first. AMP supports the long-term success of your web strategy with distribution across popular platforms and reduced operating and development costs.
• Use Google's PageSpeed Insights to analyze the content of a web page, then generate suggestions to reduce latency and make the page load faster. When pages load faster, ads load faster and viewability rates go up.
• Minimize passbacks: Ads also tend to load more slowly when ad calls are passed from one ad server to another through a system called passbacks. The fewer passbacks that happen, the faster ads can load, which can increase viewability rates.

Lazy loading

Also known as Smart Loading, it means serving ads only when necessary. This includes serving an ad towards the bottom of the page only when a user scrolls to the ad's section. Lazy loading lets pages load faster, and reduces latency and CPU consumption.

We recommend using Google Publisher Tag, since other forms of implementation might trigger multiple ad requests that don't lead to a rendered creative in the browser (which will further reduce your viewability metrics).

Lazy loading developer docs

If used properly, lazy loading can increase the overall viewability percentage. In cases where a user doesn't scroll down, for example, the below-the-fold ad slots don't load, and fewer ad requests are made. However, if the ad size is too large or loads too late, for example, when the user scrolls down faster than the ad loads, the user won't be able to view the ad.

Infinite scroll

Infinite scroll, a form of lazy loading, is when the browser scroll bar keeps scrolling but never reaches the bottom of the page, which causes the page to grow with additional content.

Dedicated video section

When you integrate a dedicated video section into your site or app, you can drive traffic directly to your videos, which typically results in viewers wanting to watch the videos. When viewers intend to watch videos, they're more likely to watch the ads within them. 

Responsive design

Build responsive ads so that they fit the particular browser used to view those ads. This provides a good user experience, regardless of which device (mobile, tablet, or desktop) they select to view your content and ads.

Try the following best practices:

• Implement Google Publisher Tags (GPT).
• Optimize your site for mobile users.
• Apply viewability best practices to each ad setup, when applicable.

Ad placement

Three criteria must be met before an ad impression is counted as viewable.

1. A user must navigate to an area of the page where 50% of the ad's pixels are visible in the browser window.
2. The user must pause or proceed slowly enough that the ad is on screen for 1 continuous second. Scrolling past an ad too quickly doesn't count.
3. The ad must be rendered when the user navigates to it.

With this in mind, we reviewed Active View data across the AdSense network and compared a broad range of site designs with high and low viewability. To help maximize the number of viewable impressions generated by your site, here are some suggestions based on our research.

Third-party creatives using <img> tags

If your creatives load third-party tracking pixels in <img> tags, you should set the display property to display:none; to ensure that only the actual size of the creative is considered for viewability.

Video ad players

Users are becoming accustomed to premium video player experiences. By increasing your video player size and using best practices for click-to-play, autoplay, and sticky players, you can grow the viewability of your video ads.

• Implement larger video player sizes: Make the video player the primary focus of the page. Large video players have significantly higher viewability than smaller video players. Typically, the larger the video player size, the more viewable the inventory.

  Example

  A 2560 x 1440 video player has a 95% viewability rate on average, whereas an 854 x 480 player size has an 88% viewability rate.

  Publishers should evaluate their video ad inventory and move away from smaller video ads that don't deliver the viewability rates desired by advertisers. This is a best practice for instream video inventory which may fill an entire screen, although smaller video players may still be appropriate for non-in-stream formats to protect the viewer experience.
• Implement Click-to-Play: Click-to-Play ensures higher user engagement and viewability because a person has to click the video to play it, showing intent to watch the video and the ad within it.
• Use autoplay the right way: Getting autoplay right is critical to the quality of your site or app experience. While muted autoplay is allowed, be sure your implementation is in line with the Chrome autoplay policy.
• Use sticky players the right way: Sticky players may not be ideal for all types of websites, such as gaming pages or dynamically evolving pages. You should make sure to thoroughly A/B test sticky ad unit performance before implementing the unit across a site or app. If you use a sticky player to improve viewability, the player must first start as a full size in-stream unit. Learn more about sticky video player policies.
• Use viewable-friendly ad formats: We recommend minimizing the use of iFrames, which is an HTML document embedded inside another HTML document primarily found on sites. Ad tags within some iFrames, such as cross-domain iFrames, can't be measured by any viewability solution, while others like friendly iFrames and SafeFrames help better measure viewability. When fewer ads run within cross-domain iFrames, viewability rates increase.

Quality control

Test and iterate as part of the redesign process. Each site is different as viewability depends on the content, vertical, and users' behavior on the site.

To optimize your viewability, here are some ideas to keep in mind:

• Position on the page matters. The most viewable position for an ad is right above the fold, not at the top of the page.
• The most viewable ad sizes are the vertical sizes units, such as 160x600.
• Above-the-fold is not always viewable, while many below-the-fold impressions are viewable.
• Content that holds a user's attention has the highest viewability.
   

More tips from Think with Google

• "3 P's of video viewability for publishers: premium experiences, placement, and player" (2019)
• “5 factors of video viewability” (2015)
• “5 factors of display viewability” (2014)