Follow the below steps on how to build a Weighted Average metric.
Step 1: Create the "Sum" metric
Within the metric builder, select 'add Defintion from template'.
Locate the metric you would like to use from the possible fields available, e.g Avg Position, Avg Quality score etc.
Edit the metric formula and multiply the metric by the Impressions.
Save this metric as unpublished, by unchecking the 'Publish' box. This will ensure the metric will not appear in the report builder but can still be used in calculated metrics.
π‘ Tip: Naming the metric β[Metric Name] Sumβ can help with clarity.
Step 2: Create the Weighed Average Metric
You will need to create a new calculated metric by building a 'Custom Metric'.
Locate the new Sum metric created and divide this by the impressions.