UX design is a concept that's core to the CLD approach. We know when it's worked because the performance metrics go through the roof.
"Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away."
This is a hard philosophy to work towards but one that wins every time. By reducing a design to it's optimum we can ensure a higher degree of clarity and purpose. All of the information gathered in the planning phase leads up to this point, having all the data isn't the end of the journey. Working out what aspects to leave out and how to simplify the complicated is where the real work starts.