Leader Keys Effectiveness System (LKES) Credentialed Evaluator Review 2021-2022 is a REQUIRED course for ALL evaluators who have been credentialed PRIOR to July 1, 2021. The course is designed to update and review all component of LKES. Credentialing is a process of establishing the qualifications and proficiency of evaluators to utilize LKES. The expectation is that evaluators continue to familiarize themselves with the LKES instrument as they work within their district.