Radiation therapy is a sophisticated complex process. Systematic methods are needed to quantitatively evaluate the quality of a complex process and hence radiation therapy treatments. An ideal result for a complex process must be established to determine if the complex process is completed acceptably. For radiation therapy, this can be accomplished through complication free tumor control probability functions. A theoretical mathematical function can be created from a treatment plan to represent its complication free tumor control probability quantitatively by exporting Dose Volume Histograms from treatment plans to create complication free tumor control probability functions. By creating a baseline treatment plan (or assuming an ideal course of treatment), a relative comparison can be performed to assess how variations in the tasks that contribute to the treatment plan affect the complication free tumor control probability. By creating a systematic method to outline how and when all tasks are performed, variations in complication free tumor control over the entire course of treatment can be established and analyzed as to their impact on the quality of treatment.