Be careful when reviewing performance at the campaign level. It's not the best way to figure out if your advertising is working well.
Many of our users analyse the campaigns of a strategy as a single entity and want to stop one of them because of its poor performance. But is it the right thing to do?
First of all, we need to understand that the algorithm does not allow us to select which campaigns to pause or run because all the campaigns work as a group.
In a strategy, each campaign has its own objective (two exploration campaigns and two optimisation campaigns), and if we start pausing one of them, the algorithm will be deprived of a component and will not be able to run at its maximum potential.
Second of all, the ACOS target is set at the strategy level, not at the campaign level.
A good performance in one campaign could compensate for a poor performance in another.
Furthermore, two campaigns are bound to perform poorly: the two exploration campaigns (auto and phrase).
When a search term converts in an exploration campaign, the search term is extracted from the exploration campaign. Time after time, only noise resides in the exploration campaigns and performance will never improve, but spending will automatically decrease due to the lack of conversion.