The Cross-Classified Mixed Effects Model (CCMEM) has been demonstrated to be a flexible framework for evaluating reliability by measurement specialists. Reliability can be estimated based on the variance components of the test scores. Built upon their accomplishment, this study extends the CCMEM to be used for evaluating validity evidence. Validity is viewed as the coherence among the elements of a measurement system. As such, validity can be evaluated by the user-reasoned desired or undesired fixed and random effects. Based on the data of ePIRLS 2016 Reading Assessment, we demonstrate how to obtain evidence for reliability and validity by CCMEM. We conclude with a discussion on the practicality and benefits of this validation method.