…the web, you can analyze usage data for your product and compare different interfaces in A/B tests. This is sometimes called “data-driven design”, but I prefer to think of it as data-informed design — the designer is still driving, not the data.
As Don Norman — known for coining the term “UX” — said it best, “The real problem with the interface is that it is an interface. Interfaces get in the way. I don’t want to focus my energies on an interface. I want to focus on the job.”
When an engineer takes a shortcut and scrimps on performance, they need to understand how that damages the user experience. Likewise, when a designer pushes an engineer to make a change that affects performance, that engineer should help the designer make the best overall design decision — not just roll over and do what the designer asked. It’s this type of respectful collaboration that makes great design happen.