This book explores the critical role of performance criteria (PC) in research and interventions for autistic individuals, emphasizing its function as a moderator between independent and dependent variables by establishing higher durability of behavioral change. In the field of autism research, it is common to target a dependent variable that focuses on either increasing adaptive skills (such as social skills, verbal language, academic, health skills, and daily living skills) or reducing destructive/problem behaviors (such as hitting, biting, wounding, screaming, and engaging in off-task behavior). While PC is commonly used to evaluate intervention effectiveness, recent studies suggest that PC levels are associated with improved maintenance and generalization of trained behaviors. Additionally, emerging research highlights the potential of PC in calculating intervention effect sizes, offering a new perspective on assessing clinical significance.Given the importance of PC in establishing evidence-based practices, this book aims to provide a comprehensive discussion on how to determine optimal PC levels for various skill domains in autistic individuals. By synthesizing existing research and offering practical guidance, the book equips researchers and practitioners with the necessary tools in terms of assigning PC levels to evaluate interventions with greater accuracy and ensure socially meaningful behavioral change.