One of the fastest-growing occupational groups in the US is expert service workers: knowledge workers who sell their expert knowledge and services on the free market. In this paper, we offer a comparative case study of how expert service workers, whom are hired for their professional evaluations, navigate the tensions of the expert service-client relation in a specific but critical way: How do they convince others that their professional recommendations are credible? Specifically, we draw on two disparate cases of expert evaluators, book reviewers and management consultants, and document two communicative patterns that these professional groups use to build the credibility of their professional recommendations: (i) transparency and (ii) distanciation. Similarities in the credibility tactics of these two sets of expert service workers from two very different worlds, the Arts and business, suggest their generalizable value. Hence, we conclude by discussing how our findings offer a general approach we call, the evaluative triangle, for studying the credibility tactics of expert claims across multiple worlds of work.