I am testing out CBO now and some are lookalike 1%, 5% and 10% so they have huge audience overlap. Some articles say overlap on CBO doesn’t matter but some say you should exclude audience from each other. Should I exclude audience or not?
I wouldn’t bother excluding them. Not because of overlap but because of overkill. Worst case scenario is you pick up the customers on an ad set that’s not the exact LAL you wanted. So what? As long as your CPA is good it shouldn’t matter in my opinion. Unless you’re dealing with massive LALs then it would make sense to force the split.
I’m not a fan of excluding audiences; I get the concern about possible overlap but agree with u/lez566’s point. It can be overkill that may even harm the performance of the algorithm. I suppose this is still in the realm of anecdotal experience, but I have not seen any benefit from excluding audiences and have been running with several LALs between 8-10 million prospects.