Background: Clinical skills examinations using standardized patients (SPs) are important in documenting the proficiency of trainees. "Standardized examinees" (SEs) are individuals trained to a specific level of performance; they can be used as internal controls in a high-stakes, clinical skills examination. Purpose: The purpose of this study was to determine whether SEs can be trained to portray a specified level of confidence and whether SPs' checklist scoring is affected by the personal manner of the examinee. Methods: Eight SEs were trained as "students" and trained to achieve a failing score on six cases in an National Board of Medical Examiners (NBME) Prototype Clinical Skills Examination. Four SEs were coached to be confident in manner, and 4 were coached to be insecure. Checklist scores were compared. Seven lay reviewers scored the SEs as confident or insecure on a behavioral assessment form. Results: SEs were not detected as simulations. There was no difference between the checklist scores of confident versus insecure SEs, but their manner was rated as significantly different on all scales in the behavioral assessment. Conclusions: SEs can be trained to a specified performance level and a desired level of confidence. In this small study, personal manner did not affect SPs' checklist scoring. The use of the SEs provides a mechanism to screen for bias in high-stakes SP examinations.