Ad impressions refer to the number of times an advertisement is viewed or seen by an audience, regardless of whether it is clicked on or interacted with. It is a metric used in online advertising to measure the reach and exposure of an ad.
While a high number of impressions may seem impressive, it takes clicks and conversions to deliver true campaign success.
Still, tracking impressions provides useful data to analyze ad visibility, saturation, relevance, and whether impression levels correlate to desired actions.
Comparing impressions across ads or timeframes also informs needed ad or campaign adjustments.
Code syntax such as iframes and security or ad-blocking software can alter the measurement of ad impressions. Learn more in Why Google Analytics Stats Differ from AdSense Stats.
Here's a quick rundown of how some major analytics platforms measure and count ad impressions:
- Google Analytics: Counts an ad impression when the tracking code sends any value for the promoted impression custom dimension. Impressions are counted only once per session.
- Adobe Analytics: Counts impressions using tracking code tied to the ad serving code. Impressions are counted when the ad appears in the browser, not necessarily 100% viewed.
- Matomo: Counts ad impressions when the ad tracking JavaScript code loads and executes on the page. This occurs before the ad necessarily appears visually.
- Chartbeat: Measures impressions by browser requests for ads rather than tracking code loads. Charts beat-measured impressions typically match DFP and Google Ad Manager numbers.
- Simple Analytics: Increments impression count whenever an ad creative loads on a page. Impressions tally separately for each advertisement.
- parse.ly: Counts impressions using embedded ad tracker code, following IAB standards. Impressions are logged when rotation code loads rather than the visual display.
So in summary, most analytics platforms tally impressions based on ad tracker code loading using the IAB defined approach. The exact timing with visual display varies.