Roles and teams
Domain expert (SME)
Also calledSubject matter expert, SME
Someone who knows what correct looks like in a specialised field, such as medicine, tax or airline pricing, and checks that the product gets it right.
In specialised or regulated domains, a product team cannot learn everything it needs from customer interviews. Domain experts validate requirements, review flows and content, and sign off on domain and compliance correctness.
On AI products their judgement has become central, because it defines the right answers that evaluations are checked against. Teams that do evals well tend to make one expert the final word on quality.
Common mistake
Letting the expert write the exam, the answer key and the grade. If the same person builds the product, defines success and judges it, the product can pass its own tests and still fail real users. Keep success metrics with the product manager.