Background <p>Review of Systems (ROS) forms are a common tool for clinical assessment and billing. However, terms on ROS forms vary widely. Understanding the variations in ROS terms and perceived definitions (or misperceptions) has implications for patient care and effective implementation of electronic health record (EHR) documentation practices.</p> Objective(s) <p>To define a representative list of ROS terms and to assess the range of perceived definitions (and misperceptions) of ROS terms among clinicians and lay volunteers.</p> Design <p>Qualitative review of ROS forms and qualitative interviews with clinicians and lay volunteers.</p> Participations/Patients/Subjects <p>Eleven clinicians in general internal medicine and internal medicine sub-specialties; 30 lay volunteers.</p> Approach <p>We employed a mental models framework approach to understand patient perceptions, accurate and inaccurate, of commonly used ROS terms. To do this, we first abstracted common ROS terminology used in medicine practices. Then, we developed consensus definitions of ROS terms with a sample of expert clinicians. Lastly, we conducted qualitative interviews with lay volunteers to assess their interpretations of these terms.</p> Key Results <p>By consensus, clinicians generally agreed on general principles of operational definitions. Yet, misinterpretations among clinicians were common, particularly with respect to timeframe, duration, and nuances of symptoms. Laypersons had varied interpretations which often differed from the clinicians.</p> Conclusions <p>ROS forms are inconsistently operationalized and defined, with misunderstandings across both clinicians and the public. Simultaneously, the forms create additional burden across individuals involved in care delivery, including patients and families. Broad terms and discussion of concerns with patients may provide an efficient alternative to meeting both billing requirements and patient needs.</p>