AdSense has incorporated your AdSense data into your Analytics account, so you can use the detailed traffic analysis Analytics provides to gain insight into and improve your AdSense performance.
Once you link your AdSense account with an Analytics account, you’ll see your AdSense performance in a separate AdSense section of your Analytics account under Content, in the left navigation.
AdSense will break down performance in some new ways, showing earnings and ad impressions based on user visits, the top sites referring users to AdSense, and the ability to see your earnings by page without having to set up URL channels.
You’ll also have access to AdSense metrics when you build Custom Reports in Analytics, giving you even more ways to view and analyze your data.
AdSense hopes this new, more detailed information about your AdSense performance will enable you to make more informed decisions about how and when to display your AdSense ads, and how to tailor your website to your users overall.