Educational research has long been plagued by a major limitation: random assignment, which is the feature that allows one to make causal inferences, can be inappropriate and also sometimes unethical. This has caused many researchers to resort to observational studies that are unable to yield causal inferences. This session presents Regression Discontinuity Design, a method that allows for the estimation of treatment effects without the requirement of random assignment. Attendees are shown how RDD can be used to permit causal inferences in gifted education research, as well as some of its specific requirements and limitations.