BACKGROUND:The 1995 Health Care Financing Administration (HCFA) guidelines stated that providers may only use the review of systems and past medical, family, social history in student documentation for billing purposes; therefore, many providers viewed the student documentation as an extraneous step and chose not to allow medical students to document patient visits. This workflow negatively affected medical student education in documentation skills. Although the negative impact on students' documentation skills is obvious, areas of deficits are unknown. Understanding the area of deficits will benefit future curriculums to prepare prospective resident physicians for proper documentation. We aimed to assess areas of deficits in documentation of fourth-year medical students according to HCFA billing guidelines. METHODS:We conducted a prospective study of fourth-year medical students' simulated chart documentations at a United States medical school from May 2014 to May 2015. We evaluated students' simulated charts from an online learning tool using simulated cases for completeness according to HCFA guidelines and analyzed data using descriptive statistics. RESULTS:We found that 98.9% (n = 90) of the charts were downcoded. Of these charts, 33.0% (n = 30) had incomplete history of present illness, 90.1% (n = 82) had incomplete review of systems, 73.6% (n = 67) had incomplete past medical, family, social history and 88.8% (n = 80) had incomplete physical exams. CONCLUSION:New curriculum should include billing guideline information and emphasize the completeness of charts according to acuity.