Code completion systems act both as a way to decrease typing and as a way to easily access documentation, both implicit and explicit. The former is typically done by completing known variable or function names, while the latter is done by providing a list of possible completions or by providing convenient views of or access to documentation. Because static type information makes these goals possible and feasible for qualifying languages, many improvements to completion systems are focused on improving the order of results or trimming less-valuable results. It follows that almost all validation techniques for this work have focused on proving how well a completion system can put a desired result at the top of the list. However, because of the lack of static type information in dynamically-typed languages, achieving the aforementioned goals is much harder, and many of the completion suggestions may even result in compile-time or runtime crashes. Unfortunately, of the work done on creating completers for these languages, little validation work has been done, making it hard to determine what improvements can be made. This thesis provides two validation techniques that provide information both on how well completion suggestions are ordered and also which completion suggestions result in errors. This information will be used to guide the development and evolution of a completion system for the Racket programming language.