Simulation is integrated into nursing curricula as a means of developing and evaluating clinical judgment, but there are few valid and reliable tools available and evaluation is not consistently theory based. When the Lasater Clinical Judgment Rubric (LCJR) was introduced in 2007, it provided a common evaluative language for assessment of clinical judgment but had limited support of its validity and reliability. Based on Tanner's Model, the LCJR organized nursing actions into eleven dimensions and four behavioral categories and defined specific actions in each which are typical of developmental phases (Lasater, 2007). The LCJR has been adopted by many nursing programs with limited support of its validity and reliability. This article attempts to organize current knowledge available on the LCJR in an effort to assess its use as a valid and reliable measurement tool, and to identify specific needs for continued testing of the instrument.