Maybe I mistake but from my experience, if your traffic is targeted, landing page design and content are good, product is relavant but CTR is low then Conversion rate will also be low. e.x. 70 hops per order or more. In this case low CTR means that most of your targeted visitiors are not interested in a product you promote, that's why most of them don't click. Those who click, sure, will buy something, but conversion rate will be not good and the number of sales will be low. In opposite, High CTR may mean that most visitiors are interested in your product, and you can expect good conversion rate (e.x. 30-40 hops per order in avarage ) and the greater number of sales.
It's never as linear as A -> B, since there are far too many variables at play.... and rather dynamically so. You should think of the sales funnel as a whole that's more than just the sum of its parts. Example: if you wrote a highly effective but misleading ad copy ("Don't buy this product from our competitors, because we're giving it for free here"), you'd surely get a high CTR but a very low conversion. Conversely (pun), if you write an honest and straight to the point ad copy ("This product won't make you rich, but it can help you make a decent side income"), you would probably get low CTR, but conversion might be pretty high, especially if the landing page copy was consistent with the ad copy. As a golden rule, your campaigns should stay consistent all the way through the sales funnel... from picking a traffic source that's relevant to the offer, from getting copy and ad creatives that work together - never against each other.
Thanks! I believe people often fail to realize the important of establishing sales funnels that work. Sometimes with the same amount of traffic, you can make significant improvement to CTR/goal completion... meaning it's often possible to improve sales with the exact same traffic you're getting, just by changing some things around in a certain way.