To determine this you'd have to analyze whether the conversion rate and/or value of the customer outweighs the lower clicks levels and/or likely higher CPC vs. the higher CTR alternatives.
bigdealioo
3:29 pm on Dec 28, 2007 (gmt 0)
conversion and customer value = same for low and high ctr ads in my case
poster_boy
3:52 pm on Dec 28, 2007 (gmt 0)
Then there seems to be no compelling reason to keep these ads.
I'd suggest deleting these under-performing ads - and creating several new ones with the eventual goal of outperforming the current winning ads on the aforementioned metrics.
RhinoFish
8:40 pm on Dec 28, 2007 (gmt 0)
yep, like gardening... plant new seeds and pull the weeds.