How Matched content can affect your metrics
If you’ve enabled ads within your Matched content units, then you can use performance reports to track the monetization performance (e.g., Impression RPM) at both the Matched content unit level, and also of the ads and recommendations within those units. However, one of the key benefits of Matched content is that it can benefit your site in indirect ways by helping to increase user engagement. Because your users are exposed to additional articles, they're more likely to visit more of your pages and spend longer on your site. The desired outcome of adding Matched content units to your site is that as your page views increase, so does your total revenue. This positive result can also cause several changes to your metrics. For example, your page revenue per thousand impressions (RPM) might either increase or decrease, depending on the characteristics of your site.
To help you understand any changes that you see in your metrics, we've put together the following notes:
If you add Matched content units to pages that didn't previously have any ad units on them, then views to these pages will now count as page views. If you're not monetizing those page views yourself (or they're being monetized through a platform other than AdSense), then your page RPM might drop. This is because your users are visiting more pages with AdSense ad code, but those pages are not generating revenue.
We've found that Matched content units placed near to regular ad units can increase the clickthrough rate (CTR) and RPM of those ad units. So while clicks on Matched content recommendations can result in more page views, the revenue generated on some of those page views might increase (both of which will impact your page RPM). We recommend looking at changes in ad unit CTR and RPM in your ad unit reports.
Other changes that you make to your site, for example, adding ad units, are also reflected in your metrics. You should consider the impact of these changes together with the effect of adding Matched content. For example, adding or removing ad units can increase or decrease page RPM across your account, likewise adding Matched content units to one of your multiple sites can affect your account-level metrics. In these situations, we recommend looking at your site-level metrics to understand the impact of Matched content itself.