What Is the Meaning of Impression in Google AdSense?

Page Impressions

Page impressions in Google AdSense tell you how many times each ad unit has been loaded. If you have three ad units on a particular Web page, when a browser loads up that page, AdSense registers one impression for each ad unit (assuming they all loaded correctly). Because of this, overall AdSense impressions are not a suitable proxy for Web traffic in general, but along with other stats they can be used to get a good idea of how individual ad units are performing.

Page eCPM

Effective cost per thousand impressions, or eCPM, is a way of calculating how much each ad unit or channel earns for every 1,000 impressions it receives. If the ad unit has not yet received 1,000 impressions, this figure is an estimate based on the impressions it has received so far. If it has received more than 1,000 impressions, this figure is the average of all impressions. eCPM is a useful way of comparing AdSense units against each other to see which might bring in the most revenue.

Page CTR

Although eCPM is a good way of estimating earnings, there are some flaws to using it alone. For example, if an ad unit has a high eCPM but a low number of actual ad clicks, this performance might not be stable over longer periods of time. You might have just been lucky with a few high-earning clicks. This is where CTR comes in; it tells you the percentage of clicks the ad unit gets based on its total number of impressions.

Considerations

Impressions alone do not provide much actionable data, as alone they can tell you nothing about earnings or the amount of clicks they get. CTR and eCPM can provide this information, but they too have limitations since they tell you about the overall performance of the ad unit and not the specific pages that the revenue comes from, unless they have been manually placed on a single page. For this information, AdSense must be linked to Google Analytics.