The difference between an ad request and an impression

In online advertising, publishers often charge advertisers based on the number of times that the advertiser's ad appeared on the publisher's website or app. The unit for this metric is impressions.

The rate that advertisers pay for impressions is Cost per mille, or CPM for short. A CPM defines the price for 1,000 impressions. For example, if an ad's CPM is $1, the publisher will earn $1,000 for a million impressions of that ad.

It's important to realize that online advertising is delivered differently from other forms of advertising. Usually, if an ad is configured to be displayed in a publisher's space (aka zone), a block of code embedded in the website or app requests for an ad moments before the web page or app appears to the user.

Depending on how the zone was configured, AdButler may select an ad from a predetermined pool, initiate an automated bidding process for that zone, or simply display a default ad. A successful request will result in an ad being delivered, i.e. appearing in the zone. The request and the delivery are separate processes, and only the latter counts when considering impressions.

In other words, just because an ad was requested doesn't mean that an ad was also delivered, or that a particular ad was delivered at that moment.

Ensuring accurate impression counts

AdButler usually keeps accurate records of both ad requests and impressions for ads that are configured within the application. However, when you use AdButler to serve ads from a third-party server, it may record an impression after it successfully passes the ad request to the server, even though it cannot confirm if the ad was actually delivered.

To ensure accurate impression counts when you're using AdButler to serve ads from a third-party server, we highly recommend doing one or more of the following:

• Enabling Accupixel, our impression tracking pixel. For more information, read Tracking statistics with Accupixel.
• Tracking the viewability metric, not just impression counts. Viewability is based on how long an ad is displayed on screen. An ad is considered viewable if it meets the minimum threshold for time on screen. Viewability can be tracked only on standard zones that have Javascript or asynchronous Javascript zone tags. For more information, read Viewability.
• Using third-party tracking pixels. To find out how to add tracking pixels to ad items, read Adding tracking pixels.