Back in September of 2010, we added support to manage AdWords Campaign Experiments (ACE) via the API. With the release of v201101, we are extending the API to allow you to fully manage your experiments, as we’ve included new experiment fields for use in reports. You can now segment your report statistics by the experiment splits as well as obtain experiment statistical significance on every statistical field (i.e. clicks, impressions, conversions, etc).
Segmentation
A new field called AdvertiserExperimentSegmentationBin is now available for you to segment your report rows in OUTSIDE_OF_EXPERIMENT, CONTROL and EXPERIMENT. Rows reported as OUTSIDE_OF_EXPERIMENT refer to statistics captured outside the experiment lifespan, which will occur when your report dateRange covers a broader time period than your experiment. Data reported as part of the CONTROL segment includes statistical values that belong to the percentage of traffic that you have configured as part of your control split. Likewise, values for the experimental split are reported with the EXPERIMENT value.
Keep in mind that adding AdvertiserExperimentSegmentationBin to your reports may potentially multiply their size by three, so make sure you use report predicates to control exactly what you want back and to define your reports in one of the GZIP compressed formats, if possible.
Statistical Significance
For every available statistical field (i.e. Clicks, Impressions, Conversions, CPC, CPM, etc) a Statistical Significance field pair is now available for you to use in some reports. These new field pairs have, with a few exceptions, the form of [field singular name]Significance, so for example Clicks has ClickSignificance as its pair. For more information about the available Statistical Significance fields per report see our Report Types page.
Significance fields have a specific range of values that goes from -3 to 3, values that correspond to three
, two 
and one 
(down and up) arrows respectively in the AdWords interface, while 0 is represented by a grayed up and down 
arrow. To learn more about Statistical Significance and its meaning visit our Help Center FAQ page. Also keep in mind that negative values don’t mean your experiment isn’t going as expected since fields that imply cost, like CPC, you most likely want to have a negative variation.
Life of your experiment data
Your experiment segmented statistics will exist as long as your experiment does, so as soon as your experiment is either promoted or deleted you will no longer able to retrieve experiment statistics. Hence, we recommend you download a last set of experiment reports right before the experiment gets promoted or deleted.
Reports Types Included
AdWords Campaign Experiments are applied at the Campaign level, therefore reports that apply to Campaigns, AdGroups, Ads and Keywords have included experiment specific fields. Specifically, the following reports have been enhanced with experiment fields: Ad Performance, Ad Group Performance, Campaign Performance, Keyword Performance and Managed Placements Performance.
As always, feel free to contact us at the AdWords API Forum.
- 
David Torres, AdWords API Team
