The CO APCD is built from the same information found on insurance claims, including diagnoses and procedure codes. However, the CO APCD is very different from insurance claims systems, physician billing systems and the millions of Explanation of Benefit letters sent to patient homes. All of those are designed to identify and track specific patients. The CO APCD however, is designed to aggregate data in order to perceive and display patterns of cost and utilization. While identification data are in the CO APCD, they are encrypted and stored separately from the utilization and cost data.