Final answer:
Heuristic evaluation is the UI evaluation approach that compares a design to established rules of thumb. It involves experts using defined heuristics to identify usability issues, contrasting with usability testing, cognitive walkthroughs, and A/B testing, which involve different methodologies.
Step-by-step explanation:
The approach to UI (User Interface) evaluation that compares the design to known principles or rules of thumb is called Heuristic evaluation. A heuristic is a general problem-solving framework that acts as a mental shortcut. In the context of UI evaluation, heuristic evaluation involves a set of evaluators examining the interface and judging its compliance with recognized usability principles, the heuristics. These heuristics are often distilled into common 'rules of thumb' that guide the design to be more user-friendly and effective.
Usability testing, on the other hand, is a method where real users interact with the product, and their performance and feedback are used to identify usability issues. A Cognitive walkthrough is a structured approach where evaluators go through the UI systematically, simulating a user's problem-solving process at each step to identify usability problems. A/B testing is a method for comparing two versions of a web page or app against each other to determine which one performs better.
When conducting a heuristic evaluation, the evaluators typically refer to established lists of heuristics such as Nielsen's Ten Usability Heuristics, which encapsulate common wisdom and best practices in interface design.