Digital and programmatic advertising models have enhanced website monetization capabilities for publishers. Today, publishers can leverage solutions such as header bidding, ad refresh, ad recover to earn higher revenue. 

But, they have also led to increased complexity, both technical and otherwise, in the ad tech industry. More and more metrics are being introduced to accurately measure the performance of websites and determine how ad revenue is actually being generated and how it can be optimized. 

In this blog post, we are going to talk about unique ad impressions- what they are, why are they important, how to calculate them, and how they differ from ad impressions and refreshed impressions.

What are Unique Ad Impressions?

An impression is counted when an ad is served on a website- basically, this metric shows how often an ad is being shown. 

Now, when it comes to unique ad impressions, it becomes a bit tricky due to ad refresh technologies. 

A lot of publishers have now started using ad refresh to earn more revenue. By using ad refresh, publishers can serve another ad to the user on the same ad unit if they are spending more time on the website.

So, the user is being shown multiple ads on the same ad unit, and an impression will be counted for each time that particular ad is being shown. 

A unique impression is then counted when an ad is served for the very first time in a span of 24 hours. In other words, a unique ad impression is the first impression that starts loading on an ad unit.

If the user sees the same ad after a period of 24 hours then it would be counted as another unique impression. 

Here’s an example to help publishers understand the difference between gross ad impression and unique ad impression:

Suppose, User 1 views ad A, ad B, and ad C, User 2 views ad B, ad C, and ad B, and User 3 views ad A, ad B, and ad B. 

	Unique Impressions	Gross Impressions
Ad A	2	2
Ad B	3	4
Ad C	2	2

Publishers get paid for every ad impression, which consists of both the unique ad impressions and all the refreshed ad impressions. 

Why is Unique Impression Metric Important?

Unique ad impression is an important metric for calculating the actual eCPM for an inventory.

Even though ad refresh is used for increasing ad revenue, the rise in eCPM cannot only be attributed to refreshed ads. eCPM can increase despite the use of ad refresh. 

Basically, the unique ad impression metric helps determine the value of an inventory. It further allows publishers to see how much eCPM is being generated because of refreshed ads and how much eCPM can be attributed to the unique impressions that have been served. 

Additionally, if there needs to be a comparison between an inventory where only unique impressions are served and one where refreshed impressions are served, considering unique impressions for both inventories is important for a fair comparison. 

Calculating Unique Impression CPM

The formula for calculation unique impressions is as follows:

Unique Impressions CPM = (Total Revenue / Unique Impressions) X 1000

This differs from the formula of calculating the gross impression eCPM, which is: 

Ad Impressions CPM = (Unique impression cpm + 1st Refreshed impression cpm + 2nd Refreshed impressions + … + Nth Refreshed impressions)/Total impressions

Unique Impressions and Refreshed Impressions

The general consensus in the ad tech industry is that ad refresh is not always the best solution.

A lot of publishers prefer to use static inventory, which is majorly because advertisers tend to reduce the payment for every refreshed ad that is served. 

In addition to this, rotating inventory can actually affect revenue generation in a negative way (in the long run) and decrease the value of the inventory. This will also decentivize buyers to bid on that particular inventory. 

The above graph depicts how eCPM decreases after every time an ad is refreshed. 

This being said, auto-refreshed ads can be an ideal solution for some publishers who are adhering to the best practices.

Ideally, a publisher needs to see how much time users are spending on their website. If the time spent is higher than usual than the website can benefit from an ad refresh solution. 

Also Read: The Case Against AdPushup and How We Resolved it

Similarly, a static inventory also has both pros and cons depending on the needs of the publishers. For instance, when publishers are focusing on enhancing user experience, it can be beneficial to steer clear from refreshed ads. 

Most importantly, publishers have to see how users are interacting with their website. If your content consists of infographics and such, ad refresh is not the solution for you.

You will actually benefit from a static inventory in such a case and will be able to monetize your website much more efficiently. 

At the end of the day, refreshed impressions are considered while calculating total revenue, which is the sum of unique impression revenue and refreshed impression revenue.

Publishers just have to see which solution is the best for them and use the metrics accordingly. 

Final Thoughts

Even though refreshed impressions can help some publishers in earning higher revenue, they still need to pay attention to the first impression metric for knowing the actual worth of their inventory. 

Amidst the rising levels of technicalities in the ad tech industry, it is important for publishers to keep track of how their ad units are performing. Unique ad impressions will do the same for publishers and further help them optimize their inventory accordingly. 

---