This dissertation consists of two main parts. First, in Chapters 1-4 I develop a framework for analysis of research on credibility (competence and trustworthiness) in audit settings and review literature by types of examined effects (determinants of credibility vs. consequences of credibility) and by examined credibility components (competence, trustworthiness, or both). In the conclusion of the literature review I suggest areas for future research. Second, in Chapters 510 I follow-up the literature review by examining one of the topics suggested in it. Specifically, I examine auditor assessments of client manager competence following a failure of internal controls, focusing on two key components of competence implied by COSO's 2013 Integrated Framework: an understanding of what to do to improve controls and a willingness to do it. Drawing on the Culpable Control Model (Alicke 2000), I predict that lack of a client manager's attempt to improve internal controls affects auditor ability to assess these competence dimensions. As a consequence, I predict that, given a relatively high prior perception of manager competence, the auditor gives the manager the benefit of the doubt, but prior communication about the control weakness mitigates this pattern. In my main experiment, 108 Big-Four audit seniors participate in a 2x2 between-participants design that varies whether the auditor previously communicated the potential for a control failure to the client manager and whether the client manager instituted the compensating control. My results support my predictions and suggest that, absent enhanced auditor communication before control failure, auditors may give managers the benefit of the doubt when managers to not attempt to improve controls, thereby discouraging managers from doing so. A follow-up experiment with 163 mTurk participants in a more general evaluation setting further supports my predictions by indicating that evaluations in the "no previous auditor communication, no client manager action" condition vary with the evaluator's prior belief about the competence of the evaluatee.