You Can't Test Everything, So What Should You Test?
Summary: Nobody has enough user-research budget to test everything, so you must focus usability testing on those features that will matter the most for the user experience and have the most business impact. Here's a simple method to prioritize what to test.
Maria Rosala is the Director of Research at Nielsen Norman Group. She leads and oversees research at NN/g, trains teams around the world on UX topics, and works with clients to help them improve the user experience of their products and services.