Using a cognitive task (mental calculation) and a perceptual-motor task (stylized golf putting), we examined differential proficiency using the CWS index and several other quantitative measures of performance. The CWS index (Weiss & Shanteau, 2003) is a coherence criterion that looks only at internal properties of the data without incorporating an external standard. In Experiment 1, college students (n = 20) carried out 2- and 3-digit addition and multiplication problems under time pressure. In Experiment 2, experienced golfers (n = 12), also college students, putted toward a target from nine different locations. Within each experiment, we analyzed the same responses using different methods. For the arithmetic tasks, accuracy information (mean absolute deviation from the correct answer, MAD) using a coherence criterion was available; for golf, accuracy information using a correspondence criterion (mean deviation from the target, also MAD) was available. We ranked the performances of the participants according to each measure, then compared the orders using Spearman’s rs. For mental calculation, the CWS order correlated moderately (rs =.46) with that of MAD. However, a different coherence criterion, degree of model fit, did not correlate with either CWS or accuracy. For putting, the ranking generated by CWS correlated .68 with that generated by MAD. Consensual answers were also available for both experiments, and the rankings they generated correlated highly with those of MAD. The coherence vs. correspondence distinction did not map well onto criteria for performance evaluation.

When seeking help or advice, one naturally wishes to get that aid from someone who does the task well, from an expert. Determining whether someone merits that label is not trivial, and the judgment can have important consequences. Experts in most domains, from athletes to plumbers, need to exhibit a high level of performance to maintain their status. But there is another group of professionals that is never examined. The expert status of such experts is conferred via criteria such as education or experience. While their credentials may be challenged, their work itself is not seen to bear upon their status. We refer to this group as privileged experts. These experts make assessments or predictions whose correctness is rarely evaluated. Even if prophecy fails, errors are forgiven. We account for this non-evidentiary perspective by positing a widely-held misconception that expertise generalizes. We outline a task-specific, performance-based, limited-term certification scheme that can supplant privilege.