Forecast adjustment details

Understand how Google applies forecast adjustments to the forecasting numbers, what happens when you adjust a forecast with a placement filter, why you can’t enter adjustments outside of a certain range, and more.

How adjustments are applied

A new adjustment is always applied to the latest forecasting numbers, which include any existing adjustments.

  • If there’s no existing adjustment over the date range: The adjustment is made relative to the current forecast at the time of the adjustment, and it won't change after that.
  • If there is an existing adjustment over the date range: The new adjustment is made relative to the existing adjustments.

Including existing adjustments in the baseline allows you to combine multiple adjustment effects with overlapping date ranges.


Initial forecast

The initial daily forecast for May 2 – 5 is:

  • May 2: 100
  • May 3: 100
  • May 4: 100
  • May 5: 100

The total is 400 predicted ad opportunities.

1st adjustment

You then apply a 150% adjustment to May 4 – 5. The forecasted numbers are:

  • May 2: 100
  • May 3: 100
  • May 4: adjusted to 150
  • May 5: adjusted to 150

The total is now 500.

2nd adjustment

You then select May 2 – 5 and update the total adjustment to 1000. We don’t evenly allocate the 1000 to 250 for each of the 4 days. Instead, we proportionally allocate them according to the value of each day, inclusive of the 1st adjustment.

The adjusted forecast numbers are now:

  • May 2: adjusted to 200
  • May 3: adjusted to 200
  • May 4: adjusted to 300
  • May 5: adjusted to 300

Filtering by placements

When filtering by placements, note that changing their ad units will affect the adjusted value for the remaining ad units. For example, if you adjust traffic for a placement by 1 million impressions, and later remove 8 of the 10 ad units from the placement, only 2 ad units will be left to share the adjustment of 1 million impressions.

Adjustment limitation

Due to a system limitation, you can only enter adjustments within a range of 20% to 300% of the average daily value of the full two-year forecast. The allowed adjustment may be narrower for some date ranges if they have points that are already close to the 20% or 300% boundary. We will widen the allowed range in a future release.

If you select a date range that contains very high forecasted values, you might only be able to adjust it upwards a small amount before hitting the 300% boundary.

Coming soon: See how adjustments affect your forecast

When you make a forecast adjustment using the new functionality, we’ll soon provide alerts and details when the adjustment affects traffic or inventory forecasting numbers. These alerts and details were available for legacy forecast adjustments.

In the meantime, to see which inventory is affected by your adjustments, click Inventory and then Traffic forecast and review the "All adjustments" section.

Was this helpful?
How can we improve it?