Advertising Glossary: Pageviews vs Impressions

In our last installment of the Digital Ad Academy, we showed you how to calculate clickthrough rates (CTR) by introducing clicks and impressions. Clicks are how many times someone clicks on an ad, and impressions are the number of times an ad is displayed.

In the world of online advertising, a common mistake is to confuse impressions with pageviews (PV), which is the number of times a page is displayed. To make things even more unclear, a pageview is sometimes referred to as a page impression.

Here’s how pageviews and ad impressions are calculated differently: Let’s say a blog has a banner ad placed above its header on all pages. A visitor opens the home page and sees the ad. So far, the blog has received one pageview, and the ad has received one impression. The user clicks through to another page, where the same ad is above the header. Now the blog has received two pageviews, and the ad has also received two impressions.

Will pageviews over a period of time match ad impressions over the same period?

Not necessarily. In the scenario above, the ad was on all pages, so the number of ad impressions was equal to the number of pageviews. If the same advertiser in that scenario had requested that the ad only be served on the home page, then the blog would have two pageviews and the ad would have only one impression.

Blogads.com sells our standard Blogads according to a sponsorsip model, which is to say that our ads appear on every page of a blog for a fixed period of time. When an advertiser visits our order page, she will see a figure that says, “up to ____ imp/wk.”  That number is based on the total number of estimated pageviews for a period of time. If the advertiser buys a one-week ad on a blog that serves 10,000 pageviews a week, it is likely that her blog will also receive about 10,000 impressions.

To recap:

Impressions = Number of times an ad is displayed on a user’s screen
Pageviews = Number of times any page has been displayed on a user’s screen
Impressions ≠ Pageviews

Sometimes these numbers are the same, but the number of impressions is often lower than the number of pageviews. If a publisher claims an ad has received more impressions than a site has received pageviews, someone is either confused or being dishonest.