All CoC accredited programs that initially diagnose a patient or that provide all or part of first course treatment report the case to the NCDB. If more than one facility submitted a report, the “best” is provided in the PUF file (PUF_MULT_SOURCE variable, coded 1), based on the most recent patient contact with the program, completeness of coded detail and/or edit quality, where differences exist. The record used in the case of ties is arbitrary. If this item is coded 0, only one facility provided a report for this cancer. This item should be used for hospital level comparisons using surgical volume, treatment, distance, or other hospital level computations in order to take into account cases treated at more than one hospital. Researchers can choose to limit hospital level analyses to only cases that received treatment at one CoC facility, or may choose to only include variables that indicate treatment was received at the facility included in the PUF. Researchers are encouraged to consult with NCDB staff to further clarify any questions regarding duplicate records and treatment in more than one facility.