How to Measure Ad Viewability

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We often talk about viewability in the digital advertising world, but it can be incredibly confusing to most people within the industry.

This is because the technology in digital advertising is constantly evolving — and quickly. This makes it difficult to nail down the standards of viewability and even its exact definition.

In this article, we’re going to dive into ad viewability, why it’s important, how to measure it, and some tips on how to improve it.

What Is Viewability?

When we talk about ad viewability, we’re talking about a digital advertising metric that tracks the ad impressions that have been viewed by real human beings (as opposed to bots).

Viewability covers the scope of impressions that are referred to as viewed impressions, which translates to the number of times a user has had the chance to view an ad — not the number of times a single ad has been viewed by users.

These types of impressions, for example, are often counted even if a user visits a fully-loaded page and leaves about a half of a second later. 

However, if your ads happen to be at the very bottom of the web page and the visitor doesn’t scroll far enough down to be able to view it, the impression won’t be recorded.

At a first glance, it may seem confusing since the metric measures an ad’s potential to be seen. However, this important metric doesn’t just measure viewable ad impressions, but also the accountability of the platform being used.

In Ad Ops’ earlier days (circa 2011), the IAB, the ANA, and the 4A’s came together to fix the issues regarding digital measurement that had been plaguing advertisers. Viewability is one of the methods they came up with, and since then, it has allowed advertisers to more effectively compare the effectiveness of their digital ads served. 

Why Does it Matter?

According to Google, 56% of all digital ads served are never even seen by users.

That’s a little bit more than half, which means that advertisers are wasting millions of dollars in ad spend every year. On the publisher’s side, this also decreases the value of their ad inventory, making it a lose-lose situation for everyone aware of the viewability metric.

This is why viewability is so important, and why the digital ad industry has shifted their focus from served impressions to viable impressions.

According to the IAB, digital measurement is arguably the single greatest challenge that most digital advertisers and marketing agencies face. Most advertisers still measure the effectiveness of their ad campaigns by evaluating the usual metrics, like click-through rates (CTR), and cost per mille (CPM).

While these metrics may be the industry standard used to track an ad campaign’s effectiveness, the results can often be inaccurate — one of those reasons being invalid traffic, like bots.

Inaccurate measurement results means that an advertiser is paying for impressions that may or may not be human, which equals a waste of money.

So, what makes viewability so special?

Here are a few reasons why viewability is crucial to your metrics:

  • Viewability ensures that you’re tracking real human views rather than bots.
  • Viewability allows advertisers to track which ads are doing a better job of motivating active viewership as well as engagement.
  • Viewability can give advertisers direct insight into ad performance based on where ads are placed as well as where to place them so they’re more likely to be viewed.

The fact that viewability ensures that you’re tracking real human views during an ad campaign is enough to emphasize the metric’s value. For advertisers, it helps to know that their advertising costs can be reduced simply by working with an ad platform that sets its pricing based on viewable impressions.

Of course, there is also value in measuring viewability for publishers. For publishers, viewability helps you understand the real performance of each ad placement space on a web page. This means you can re-evaluate your ad placement based on viewability technology to better fulfill the demands of advertisers.

What Are Viewable Impressions and Active Views?

Time to go into more detail about viewable impressions. Essentially, every time a digital advertisement shows up somewhere on the internet, it’s referred to as an impression, as we mentioned earlier.

However, impressions have three classifications:

  • Served impressions
  • Eligible and measurable impressions
  • Viewable impressions

Served impressions are the ads that are served, counted, and analyzed based on server data. While it’s possible to track regular impressions, server data doesn’t support data analysis that involves user behavior. Hence the issues with invalid traffic.

When we talk about eligible and measurable impressions, we’re talking about the ads that are downloaded and then stored on users’ mobile devices. These types of impressions are usually taken into consideration when counting legitimate impressions, even if the ads haven’t been shown to the user yet.

When it comes to viewable impressions, any relevant viewable ads are measured as a percentage of the ads seen by human audiences. In other words, ads that are displayed for longer than one second and are more than 50% visible pixel-wise.

When you break down the various categories of ads in terms of the viewability metric, the measurements look like this:

  • Display ads – There must be a 50% minimum of ad visibility for at least one second. The ad itself should be less than 970 x 250 pixels.
  • Video ads – There must be a 50% minimum of ad visibility while the video is playing for at least two seconds.
  • Connected TV ads – These must be served through a premium publisher and the video must play for at least two consecutive seconds.

So, what is active viewability?

When you hear the term active view your mind probably goes straight to thinking about what counts as an impression and what doesn’t. However, an active view is a mixed reality capture (MRC)-approved tool used by Google to measure and report your ad viewability. The tool determines whether the impressions were viewable and for how long.

Active view reporting provides measurement data that offers insight to publishers of the number of viewable impressions that their website has generated. This data, specifically, can be used to later enhance their site’s overall viewability.

What Causes Ads to Not Be Viewable?

The primary cause of ads not being viewable is poor ad placement. When ads are placed in spots where human users never see them, they are virtually useless.

One of the most common examples of this is an ad being hidden behind another browser or tab.

The following are the usual scenarios causing ads to not be viewable:

The Ad Isn’t Positioned Above the Fold

The phrase “above the fold” refers to the top part of the web page. You can picture it as the portion of the web page that’s visible without having to scroll further.

This issue usually has to do with both the design of the web page and the placement of the ad itself. Plus, users are viewing web pages with various devices — specifically, smartphones. Therefore, screen size comes into play for viewability, which is why optimizing your website for mobile use is a necessary step.

When an ad loads below the fold, whether it’s due to a small screen size or poor placement, it won’t be viewable unless the user scrolls down.

The User Is Using an Ad Blocker

Many users today use ad blocking services that work via browser plugin or filter. These services work to either hide the ads or prohibit them from loading in the first place.

Some ad blocking services only scan a web page after it has loaded and search for HTML patterns containing “ad” in the code.

Essentially, to an ad network, the ad still counts as served, and a regular impression may be recorded, even if it wasn’t visible on the screen. When you implement viewability measures, you’ll be able to tell if the ad is actually visible and whether or not a user sees it.

Invalid Traffic

Invalid traffic refers to non-human or bot traffic that is programmed to spike impressions and CTRs. These forms of invalid traffic are usually automated and falsify traffic, contributing to ad fraud.

This causes ads to be not viewable by real humans as the invalid traffic is taking up all the impressions.

The User Has Multiple Tabs Open

Your ad may be playing but that doesn’t mean the user is watching — which may be because they are on another page at the time.

This is actually very common among desktop users. Users will click on another tab to browse through a different page while the ad plays through simply because they don’t want to watch it but can’t skip over it.

How to Measure Ad Viewability

The Media Rating Council (MRC) has a set of viewability standards and definitions for advertisers and publishers to refer to. We mentioned some of those standards earlier, but to recap, here’s what it takes for an ad to be considered viewable:

  • Desktop display ads require a minimum of 50% of the ad view for at least one second.
  • Desktop video ads require a minimum of 50% of pixels in view for at least two seconds.
  • Large desktop ad units require a minimum of 30% of pixels in view for at least one second.

The MRC has also proposed the same viewability standards for mobile devices. However, viewability standards are constantly under development, and there currently aren’t any consistent standards for custom ad units for mobile ads.

Viewability Measurement Rates

Viewability measurement rates are usually expressed as a percentage. However, advertisers are not yet able to measure 100% of their total ad impressions thanks to the above scenarios that render ads as not viewable.

Therefore, advertisers use measured ad impressions to get the rates they need. Measured ad impressions are expressed as the number of total viewable ad impressions divided by total measured ad impressions. That number is then multiplied by 100 to get the percentage.

The formula looks like this:

Viewability Rate = (Total Viewable Ad Impressions / Total Measured Ad Impressions) x 100

How to Improve Ad Viewability

Now that we understand how to measure ad viewability as well as what causes ads not to be viewable,  we’re going to talk about what you can do to ensure that your ads have a better chance of being seen.

Change the Ad Slot Position

Ads positioned above the fold have the best chance of being viewed. This doesn’t mean you should completely count out ads below the fold, especially since these slots are more cost effective. However, you should try to get as many ads as possible in prime positions to increase the chances of viewability.

Pay Attention to Ad Size

Ad viewability on certain ads, like vertical ads, are higher than others. This is because vertical ads can span the entire page as the user scrolls.

You can also try implementing sticky ads that stay visible within the browser viewport, which yield higher CPMs in addition to viewability.

Optimize for Mobile Devices

Mobile devices tend to produce higher viewability rates compared to desktops and tablets. This is because they load faster, which means the ads load faster, which equals more viewing potential. Take the time to optimize your website for mobile devices. It’s worth it.

Try Lazy Loading

When you set your page to lazy loading, the ads will only load once their slot is in the user’s viewport. This not only improves ad viewability, but it also reduces pahe weight which allows for a quicker page load time since it uses less initial resources.

Fix Any Page Latency

Page latency can negatively impact the entire user experience as well as your CTR. If the page takes a long time to load, there’s a chance that the pixels won’t fire for longer than one second when in the user’s viewport. Focus on improving your Core Web Vitals.

In parting

Without a doubt, viewability will continue to grow as an important metric as more and more advertisers and publishers continue to use it to track their overall ad performance.

What’s important is that you choose the right Ad Ops partner to help you out with the complicated stuff.

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