Underdelivery

Definition

Deliver fewer impressions, visitors, or conversions than expected over time.

Information

Underspreading can occur for several reasons. A website or network may experience an unexpected drop in traffic. Low CPM campaigns can be replaced with high CPM campaigns. Performance percentages can be exceeded for all CPM campaigns, and there is an additional risk that ad units may not get the expected response.

As a general rule, it's a good idea to fix the negative pressure issue before the ad purchase is complete, rather than trying to close a deal afterwards.