Fixing major usability, coherence, and cognitive problems can have a major impact on conversion rates. In fact, the capacity for abstract rational thought is only a recent evolutionary addition to our brains.
Often, the details of good coherence have already been formally codified in your company's visual design brief document. One often-ignored aspect of landing page testing is coherency. Coherency is an overall sense of your design "hanging together.
Fixing major usability, coherence, and cognitive problems can have a major impact on conversion rates. In fact, the capacity for abstract rational thought is only a recent evolutionary addition to our brains.