We are always striving to make sure the data you fetch from the AdWords API is as meaningful as possible, and in v201406 we've made a few changes to some return values that should be more intuitive.

First, in the TrafficEstimatorService, we used to return 0 for values which we couldn't calculate, for example if a field requires division by zero. However, this could’ve given the false impression that the actual value was 0, rather than that it couldn't be calculated. For this reason, we’ve changed the logic to return null in cases where the value couldn't be calculated at all. This affects the averageCpc and averagePosition fields in StatsEstimate, as these values will not be returned in SOAP responses when they can’t be calculated.

Second, when using the Keyword Performance Report, we formerly returned all negative keywords as having a "pending review" approval status. Since negative keywords don't need to go through the same process as normal keywords, we will now return a null value instead for the ApprovalStatus field for all negative keywords.

This change only affects version v201406 going forward, and doesn’t affect existing versions v201402 or v201309.

As always, we are constantly looking to improve the API. If you have any questions about this or other API features, please feel free to ask on the forum or on our Google+ page.