Your performance may fluctuate if your bids, bid limits, or bid targets are set without taking into consideration the historical data Google Ads will use to serve your ads.
What you can do
When setting bids, bid limits or targets for your bid strategy, leverage historical data and related metrics to understand if the bids, bid limits or targets you are setting are appropriate to maintain performance.
If you have been losing impression share due to ad rank with your current bids, setting a lower bid limit than your current average CPCs can potentially cause further performance fluctuations.
For Smart Bidding, we recommend using historical data and choosing bids within a close range of the actual averages to minimize fluctuations in performance.
If your campaign is using the Target CPA bidding strategy and the conversion action targeted has seen actual average CPAs of around $10 for the past 14 days.
If the set Target CPA is lower, you may see fluctuations more frequently. The reason for this is that the campaign may need to decrease spend periodically, depending on the CPA it is achieving, as it optimizes to ensure the achieved CPA is within that lower target on a monthly average basis.
Need something else?
Check other common reasons why your campaign performance is fluctuating.