Google unveiled a new and improved ad preview tool back in January. The tool's purpose was to give users the ability to view their ads without incurring extra impressions and clicks.
This new preview tool also allowed users to view ads by region, state, city, country, or custom locations. Also, users can preview via high end mobile devices and even by mobile service providers.
Now Google has incorporated a diagnostic tool within the preview feature. The diagnostic tool is integrated within the AdWords dashboard under the campaigns tab and also in the keyword research tool.
Gone are the days where we have to trust Google's word they are displaying our ads for users in a specific region or search engine results page. Now we can see which keywords are showing the ads and which ones aren't displaying the ad, and why they aren't displaying.
If the keyword, or SERP, is not displaying the ad, the new diagnostic tool will show why the ad is not being served. For a quick overview, a user can filter all keywords set to an inactive state, very handy for troubleshooting keywords that require further investigation. A user can filter results by any one of the 17 statuses associated with active or inactive adverts.
The bottom line is the new features allow users to be much more thorough ensuring placements and targeting is set up correctly.