Device column within Ad performance tables causes impressions and clicks to be under counted

[Raghu Kashyap]

The moment we added the device column within the ad performance table the number of impressions and clicks dropped down to almost 10% of the actual value.  Is there a setting or something where if the device was not identified and the value was null we drop those records with the API download?

[Joyce Lava]

Hi Raghu,

By default, the ads will be shown in all devices and you can select the device type to which you can increase or decrease the bid adjustment based on your requirement. That said, the Device field of the Ad Performance Report will not return null values as this represents the Device where the impression was shown. 

Additionally, since the Device column is a Segment by nature, this may be the cause why the impressions and clicks are being dropped down when adding Device column in the selected fields. This means that the metrics values (e.g. Impressions, Cost, etc.) may be splitted into multiple rows.

Best,

Joyce, AdWords API Team