AdSense Coverage Reveals Wasted Ad Inventory

Sites that rely on Google AdSense to fill ad inventory may find that the largest ad network on the planet isn’t so lucrative anymore.

Google built its giant ad network in part with the help of millions of partner websites. For many years, the search giant sold and shared ads on those partner sites and gave them 68 percent of the ad revenue.

Likewise for many years, Google shared data about the performance of the network in its quarterly financial statements. The statements showed a steady increase in the amount of revenue for partners.

Several years ago, the reports changed and offered less information about the partners. At the same time, some partners began to report declining revenue.

Google apparently was keeping more high-quality quality and better-paying ads for itself. Logically, the company made the move to maintain the growth rate of its profit, revenue and stock price.

After all, keeping 100 percent of the ad revenue is much better than giving 68 percent to partners and keeping 32 percent for itself.

Declining ad revenue for partners shows up in three ways:

1. Lower cost per click
2. Lower click rate
3. Lower coverage

What is AdSense Coverage?

AdSense coverage is the percentage of ad impressions that are filled with an ad. For example, a site with 98 percent coverage has only 2 percent of the total impressions that are blank or filled with something else.

Publishers can find their AdSense coverage by logging into their accounts and clicking on Reports. The resulting default report will show the most recent seven days. A 30-day report is better.

In the top left where it says “Report By” and Days, change Days to Sites. In the tabs above the graphic, click on Custom on the far right. The result will show the average coverage for the entire site.

The ad unit report is even more useful. Again at the top left, change “Sites” to “Ad Units” and click on apply. The Custom report will show the coverage for each ad unit.

Anecdotally, sites are reporting a decline in coverage. Using the above example, some sites that had 98 percent coverage a year ago have 80 to 90 percent recently.

What to Do About Declining Coverage

Even if coverage isn’t declining, the Custom report is not likely to show 100 percent. The gap between 100 and the actual number indicates wasted inventory if nothing else is displaying.

Small site publishers can take an easy step and make sure that AdSense has a backup ad for each display unit.

In AdSense, click on Ads and Ad Units. Open an ad unit, click on If No Ads available and fill the box with a link that goes to a house ad or another ad network.

But that approach is limited to a single link. The better approach is an ad delivery platform. For example, Google Ad Manager, formerly known as DFP, is a free service that can deliver ads from multiple sources including AdSense, house ads, direct sales clients and more.

Although GAM has a steep learning curve, it is a useful tool for any site that wants to improve both ad coverage and average CPMs. Waste not, want not.