Targeting settings (Audiences, Keywords, Geo)
If your campaign is targeting a smaller group of users with very specific audience, keyword, location, or language settings, it may also be more likely to have performance fluctuations. More granular targeting translates to fewer eligible auctions that your campaign is eligible to enter at any given time.
You may notice larger changes in spending or serving if the competition increases or decreases in this smaller set of eligible auctions, because there are fewer auctions the system can enter and win to improve performance.
What you can do
Consider expanding your campaign’s targeting to increase the number of eligible options and improve the potential reach of your ads.
If you are targeting keywords, use the search terms report to review the actual searches that triggered your keywords. Compare two time periods to identify which search terms contributed most to the performance fluctuation.
Targeting overlaps with other campaigns or ad groups
You may have multiple campaigns or ad groups in your account that are eligible to enter overlapping auctions due to similar keywords or other targeting (for example location and language targeting). If there is overlapping targeting, traffic may primarily go to one of your campaigns.
Example
What you can do
Review your campaign’s targeting and consider updating the targeting so it doesn’t overlap with other campaigns in your account.
Need something else?
Check other common reasons why your campaign performance is fluctuating.