Continuous test administration of the USMLE is available to all examinees. For Step 1, Step 2 Clinical Knowledge (CK), and Step 3, which are the computer-based testing (CBT) components of the USMLE program, test scheduling and delivery are provided by Prometric. These CBT examinations are currently administered at approximately 335 US/Canadian Prometric test centers and approximately 100 international Prometric test centers. Additional test centers are located at four medical schools in the United States. The Step 1 and Step 2 CK examinations are administered worldwide; the Step 3 examination is administered only in the United States. For each of the Step examinations, once the registration process is completed, applicants make their own appointment to take the examination at a location and time most convenient to their schedule. Examination results are processed continuously, and scores are reported weekly. Individual score reports are made available to examinees via a secure website. A pass or fail result is provided, as a USMLE recommendation, for each examinee. Passing results are based on achievement of specified levels of proficiency established prior to administration of examinations. Statistical procedures are employed to insure that for each Step, the level of proficiency required to pass remains uniform across forms of the examination. As noted in the USMLE Bulletin of Information, the score required to meet the recommended level of proficiency is reviewed periodically and may be adjusted without prior notice. Notice of adjustments is posted in the USMLE Announcements. The USMLE Score Interpretation Guidelines provides score interpretation information for Step 1, Step CK and Step 3 examinations.