Let these answers provide you with the who, what, how, and why of system review recording. You know a review of systems (ROS) is a factor in determining an evaluation and management (E/M) service level, but do you know how many systems you should count for a specific level? More, do you know how you should document the review? Here are four questions for you to answer that will help you understand how ROS fits into the E/M equation. We’ve also provided some expert opinion to add depth to your E/M coding skills. Question 1: Why is an ROS needed? Question 2: What are the different kinds of ROS, and how do they help determine the E/M level? Question 3: Who can record an ROS? Question 4: How do you document an ROS? Think you know the answers?