This page highlights some important reporting concepts, some of which may be considered non-intuitive.
Segmentation
For more detailed statistics, you can split the data by segments. For example, you might be interested in knowing the number of impressions specific to the Google Search Network, separate from the Google Display Network; in which case, you will want to segment your report by network.
Segmentation, which is available in the UI as a separate menu, is achieved in
the API by just adding the proper field to the report. For example, adding the
field AdNetworkType1 to an Ad Group Performance report will result
in a report where there is a row for each ad group and network combination, with
the statistical values (impressions, clicks, conversions, etc.) split between
them. While in the UI only one segment at a time can be used for display, with
the API you can combine multiple segments in the same report. Keep in mind that
the amount of rows can increase exponentially for each additional segment field
included in your report.
Implicit Segmentation
Every report is segmented by its unique key. For example,
KEYWORDS_PERFORMANCE_REPORT
is implicitly segmented by Id and AdGroupId, even
though they are not included in the selector fields, because a keyword is
identified by both Id and AdGroupId.
Keyword,MatchType,Impressions Keyword1,Exact,3 Keyword2,Exact,10 Keyword3,Exact,5 Keyword4,Broad,4
Single and multiple attribution
When an impression occurs on the display network, the criteria that play a role in it occurring can be accounted in one of two ways: single or multiple attribution.
Single
With single attribution, only one of the triggering criteria (e.g., keyword, placement, audience, etc.) will be recorded for a given impression. The Criteria and Keyword reports follow this model. Each impression is counted exactly once (under one criterion); adding up all the criteria will give you values that match the totals in multiple attribution reports. The impression is attributed to either the best matching criteria from the bidding dimension, the best matching criteria from dimensions with bid modifiers according to the old ordering of bids (see this blog post for old ordering), or lastly, the best matching criteria from dimensions without bid modifiers according to the old ordering of bids.
Example
Keyword / Placement,Impressions www.example.com,2 www.example.ca,2 www.example.net,2 Computers & Electronics,2 Sports,2
The example above shows a Criteria Performance Report (single attribution) of a campaign targeting only the Display Network and only using verticals and placements as criteria. The report shows 10 total impressions across 5 rows, one row for each of 3 placements and one row for each of 2 verticals that triggered impressions—each getting two impressions.
Multiple
With multiple attribution, up to one criterion in each dimension that triggered the impression will have the impression recorded for it. For example, the Display Topic and Placements reports follow this model. As opposed to single attribution, multiple attribution reports should NOT be aggregated together, since this may double count impressions and clicks.
Example
Topic,Impressions Computers & Electronics,6 Sports,4 Placement,Impressions www.example.com,4 www.example.ca,3 www.example.net,3
If you target Display Only with verticals (topics) and placements, and run a Display Topics report, you'll get one row for each vertical (topic) that triggered impressions. Likewise, a Placements performance report will return one row per impressions. These reports are covering the same impressions, because up to one vertical and one placement will both be attributed to each impression.
KeywordId=3000000
In single attribution reports, all keywords that triggered impressions on the
display network will be represented by a special keyword (text:
Content) with ID 3000000.
Example
Keyword ID,Impressions 23458623485,2 23655322314,2 23953456345,2 3000000,4
If you target keywords and placements for Display Only and run an Ad Performance report, you'll get a row for each ad and triggering criteria combination for placements, and a single row with ad and ID 3000000 which accounts for all the display keywords that triggered that ad (where single attribution chose the keyword rather than a placement).
KeywordId=3000006
A criteria ID of 3000006 represents stats associated with the Display Campaign Optimizer.
Format of various fields
While all fields returned in
reports have a Type, the actual values returned won't always match these
values. Always check the Notes column, which will often have additional
information about the expected format of values. For example, ConversionRate's
Notes column states: Percentage returned as "x.xx%".
Money fields in reports
Fields of type Money are returned in micro currency units
(micros), e.g.: $1.23 will come back as 1230000 (1.23 x 1,000,000).
Micro amounts always refer to the account's local currency.
When filtering on money fields, you will have to provide the value in micros.
For example, WHERE AverageCpc > 1000000 will return rows where the
AverageCpc is greater than $1 (one unit of the account currency).
Two Dashes (--)
A value of two dashes is used to indicate there is no value for this cell.
