Domain Experts / Subject Matter Experts / Industry Experts have invaluable knowledge that you can (and should) apply during your UX process. Domain expert involvement is not an alternative to UX research, and a domain expert is certainly neither a “user expert” nor a designer.
Interviews
Domain Expert Interview — UX Knowledge Base Sketches
Knowledge
User Interviews: How, When, and Why to Conduct Them — NN/g
User interviews have become a popular technique for getting user feedback, mainly because they are fast and easy. Use them to learn about users’ perceptions of your design, not about its usability.
Interviews
User Interviews: How, When, and Why to Conduct Them — NN/g