Your account manager can enable the “Allow overlapping adjustments” setting that, with certain limitations, permits you to create forecast adjustments that overlap. This is a change from the default behavior in which forecasting adjustments that overlap cannot be entered into the system.
Default behavior
Conflicting adjustments
Two forecast adjustments are considered conflicting, and are not allowed, if they meet any of the following criteria:
They’re of the same type (manual or historical).
- They’re on the same ad unit or on a parent or child of the same ad unit (i.e., the same inventory branch).
They're applied to an overlapping date range.
- They’re for the same sizes (if they specify size).
Hierarchy of adjustments
When you enter non-conflicting forecast adjustments that have an overlapping time period, they follow a hierarchy of rules:
Manual adjustments take precedence over historical basis rules.
- Adjustments that specify size take precedence over those that don't.
With “Allow overlapping adjustments” enabled
If your account manager enables this setting, you can create adjustments on ad units that are:
in a child-parent relationship (or generally in the same inventory branch), and
of the same type, and
- apply to the same time period.
Even with this setting enabled, adjustments of the same type, during the same time period, on the same exact ad unit are still considered conflicting and aren’t allowed in the system.
How overlapping adjustments are combined and distributed
The forecasting system prioritizes overlapping adjustments in the following order:
Manual adjustments take precedence over historical basis rules.
If a child ad unit is adjusted, then when the simulation is run, the child adjustment is used if the impression is for that child; and the parent ad unit adjustment is used if the impression is for the parent.
If a parent ad unit is adjusted, but its children ad units are not, then that adjustment is distributed among the children ad units in proportion to the impressions they’ve received over the past 28 days.
Adjustments that specify ad unit size take precedence over adjustments that don’t.
The graphics below illustrate how adjustments are applied with "Allow overlapping adjustments" enabled for your network.