Signal Vitals Metric Definitions

Inventory

Viewability 

The percentage of impressions that were more than 50% in-view for at least one second, matching the definition of viewability from the MRC.

High attention impressions 

The percentage of impressions that were more than 50% in-view in front of an active user for at least five seconds.

Ad attention 

The average time each impression was more than 50% in-view in front of an active user.

Ads to content ratio

The number of ads that are in the viewport on average for the entire page.  

This metric measures the number of ad slots on the page and the length of the page compared to the size of the device viewport. So if a page has ten ad slots and is five viewports long, the ads to content ratio would be two.

Scroll depth

The average percentage of the page’s total length that users scroll through.

Page attention 

The average time users actively spent on the page.

Active user

A user that has interacted with the page in the last five seconds. Possible interactions include:

• Scrolling

• Clicks

• Keystrokes

• Mouse movement

Demand

Impression CPM

The average CPM of impressions won through Prebid.

Bid Rate

The percentage of auctions that receive a bid from Prebid.

Bid CPM

The average CPM value of bids received through Prebid.

Bid Density 

The average number of bids received from Prebid per auction.

Win Rate

The percentage of bids that win the impression after winning the Prebid auction.

Prebid Share of Voice

The percentage of ad impressions won by Prebid.