In this article, A. Adrienne Walker introduces the concept of person fit to education stakeholders as a source of evidence to inform the trustworthiness of a test score for interpretation and use (validity). Person fit analyses are used in educational measurement research to explore the degree to which a person's test score can be interpreted as a reasonable estimate of her achievement level. Although much academic literature has been produced on person fit, the findings and implications of this research remain largely unknown to education stakeholders. Walker argues that the practice of using test scores based on misfitting response patterns is problematic, and by including individual person fit in quality procedures, assessment research, practice, and policy can improve the way educational assessments serve instruction.