Key answer
A professional role asks AI to infer a way of working from an identity; analysis criteria specify directly what you want checked. You can combine them or use criteria alone.
Full explanation
“You are a senior editor; take a look” does not specify grammar, facts, structure or communication impact. “Check whether every conclusion has support and identify paragraphs with missing reasoning” narrows the work. Anthropic's official guide recommends explicit outputs and constraints. That is product-use guidance, not a controlled experiment showing that criteria outperform roles on every task. Official guide
Role studies do not settle this comparison either. Q001's experiments mainly compare adding an identity with not adding one; they do not establish that replacing a role with criteria is necessarily better. Principled Personas
If you know what good work looks like, state the criteria. If not, ask AI to propose candidates and confirm them before execution. For example:
I want to review this beginner tutorial but am unsure what to check. First suggest review criteria relevant to the problems you see, explaining what each would inspect. I will confirm which criteria to use for this review.
Roles quickly indicate a broad perspective; explicit criteria define scope, reveal omissions and support before/after comparisons. Avoid an endless list: retain only what this task actually needs.