data difference - aggregated vs breakdown reports

[Vikram Tiwari]

The issue is:

- When API is queried for aggregated data, sum of a numerical column (impressions, clicks, cost etc) is X

- When API is queried for data with multiple breakdowns (ad, adset, campaign and more), the resultant sum is X +/- n

The reason for the discrepancy of n is unknown but is suspected/theorized to be:

- An element from breakdown (ad, adset or campaign) was deleted hence during breakdown that data is not available, but when the data is queried as aggregate that data is present and thus the difference.

Any comments?

Normally the difference is in the range of +/-10 so something else might be in play here as well.

[Shwetha Vastrad (AdWords API Team)]

Hi Vikram, 

Could you provide the report definitions for these requests along with your clientCustomerId? In multiple attribution reports, up to one criterion in each dimension that triggered the impression will have the impression recorded for it. If you are using multiple attribution reports, you should NOT aggregate the results, since this may double count impressions and clicks. Please use Reply privately to author when responding. 

Regards,
Shwetha, AdWords API Team.

[Zweitze]

I know this is the case when clicktype is included in the breakdown - in that case impressions and average position will have different values.

It's easy to understand how that can happen:
With clicktype you can get separate values for sitelink impressions. So, for instance a report may state that the ads themselves got 20 impressions, and sitelinks got 4 impressions. The aggregated report will just show 20 impressions.

If you find another reason, please share it with us!