Discrepancy between monthly and daily averages

[Wes Thompson]

I am querying the ADGROUP_PERFORMANCE_REPORT to get Click-Through Rate and Cost per Click and I've noticed a large difference in numbers when querying monthly and daily data.  I was selecting the data by Month originally which was returning an average CTR of about 3% for March.  But when I switched to querying it by Date, it was returning a CTR of about 8% for the month of March.  This is true in the exported excel sheets as well from the AdWords UI.  I exported data for the month of March twice (one using the Month segment and one using the Day segment).  The value for March in the Monthly excel sheet is about 3% while the average for March in the Daily spreadsheet is about 8% (when I average together every day of March).

I was assuming that when I query the API by month, it would be averaging the daily data for me and just returning one value for the month.  So my question is: How in the world are you calculating the data so that the data returned for one month can be so vastly different from the averages of the daily data for that month?

[Luis Xander Talag (AdWords API Team)]

Hi Wes,

It seems your question is about how the AdWords calculates its data in reports. That said, since the UI report and API report are returning the same data, it is already more of a product level concern rather than specific to the AdWords API. I would suggest to post your concern in the AdWords Community Forum as they are better equipped to assist you.

Thanks and regards,

Luis

AdWords API Team