The illusion of transparency in performance appraisals: When and why accuracy motivation explains unintentional feedback inflation

•Past research suggests that managers inflate performance feedback intentionally.•We show that managers also inflate feedback unintentionally due to a cognitive bias.•Managers overestimate how accurately their feedback is communicated to employees.•Transparency illusions were most pronounced for negative (vs. positive) feedback.•Bias awareness, accountability, and incentives eliminated transparency illusions.