Single-Subject Design is a research method used primarily in fields like psychology and education to assess the effects of an intervention on an individual. This approach focuses on one subject at a time, allowing researchers to closely monitor changes in behavior or performance before, during, and after the intervention. It often involves repeated measurements to establish a clear baseline and evaluate the impact of the treatment. This design is particularly useful for tailoring interventions to individual needs, making it a valuable tool for practitioners. By analyzing data from a single subject, researchers can draw meaningful conclusions about the effectiveness of specific strategies, contributing to evidence-based practices in fields such as behavioral therapy and special education.