vCPM, or viewable CPM, is a pricing model measuring how many users view a specific ad, as opposed to a whole website page. Mobile brands will only pay for campaigns with verified impressions, so before deciding how much to pay for a campaign, they need to understand its vCPM.
According to the Media Rating Council (MRC), a “view” has to meet a certain set of criteria: an ad must cover at least 50% of the user’s screen for more than one second (two seconds for a video). If an app owner doesn’t place their ads in the correct spot, and users can’t properly view the ads as a result, the advertiser doesn’t have to pay for the transaction.