In January 2015, the FAA released a congressionally mandated, final rule on Safety Management Systems (SMS) for Part 121 air carriers. Since organizations must implement SMS, often at considerable expense, a sound, valid means of measuring SMS effectiveness must be established. The purpose of this research was to develop a model to measure and test SMS effectiveness. It was constructed through a systematic series of steps, ensuring accomplishment of research objectives. While preliminary, this research demonstrates that Data Envelopment Analysis (DEA) models can be produced to help organizations measure the effectiveness of their SMS and determine how to improve SMS-related performance.