An impression is typically defined as an instance in which a digital advert renders on a user’s screen.
Impression metrics can help make the visibility of an ad more tangible than offline advertising, where there is no specific data to understand how many people have seen an ad.
The bidding type that is used when impressions is the primary metric is CPM, or cost per thousand, bidding.
The term impressions may also be used in the context of SEO to describe when a search engine listing appears on a search engine results page. This page focuses on its definition in the context of pay per click (PPC) advertising.
How can impressions be used in digital marketing?
Some ad campaigns are conducted with the simple aim of spreading brand awareness. The number of people who have viewed an ad can be used to measure the success of such publicity drives. This is because the goal is to spread awareness and not necessarily to generate conversions.
If a brand manager commissions a billboard ad, they have no way of measuring how many people have seen it. Online banners, on the other hand, can make use of the impressions metric to accurately quantify how many people have seen their ad and check if they are making a return on their investment.
There are different types of impressions marketers can use to measure the visibility of ads.
Served impressions measure when the digital ad is transmitted and served.
It therefore doesn’t tell marketers if a user has genuinely seen an ad. Whilst an ad may have been on a page they clicked on, it may have been blocked or un-viewable. There is also a danger that the user did not scroll down far enough to see it. In this sense, served impressions as a metric are somewhat limited.
Viewable impressions go far more in-depth as to whether or not a user has seen an ad. The data will consider a number of factors to determine if an ad has in fact been viewed. While the definitions for viewable impressions varies between platform, these conditions are commonly required:
- It must be 50% viewable on the screen with the user on the page for 1 second or longer
- The user must not have any kind of ad-blocking software which makes the commercial invisible
- The user must have the necessary plugins installed or enabled for the listing to appear
Because of this, viewable impressions allow for far greater ROI assessment than standard served impressions because marketers will not be paying for ads that a user may not have even seen.