Although the field of school psychology has made progress toward the use of tests and assessment practices with empirical support over the past 20 years, many school psychology practitioners still engage in what can be described as low-value value assessment practices that lack compelling scientific support potentially taking time and resources away from practices that have a demonstrated evidence-base. Why do school psychologists engage in questionable assessment and interpretive practices despite decades of discrediting scientific evidence? This article critically examines several plausible explanations for the perpetuation of low-value practices in school psychology assessment. It also underscores the importance of critical thinking when evaluating assessment and interpretation practices, and discusses practical recommendations to assist in advancing evidence-based assessment in school psychology training and practice as the field progresses well-into the 21st century.