The National Ambulatory Medical Care Survey: a resource for understanding the outpatient dermatology treatment.

The National Ambulatory Care Survey (NAMCS) collects information on outpatient medical care in the United States. Key characteristics of the NAMCS methodology are not well recognized. We describe the NAMCS survey design and patient visits to dermatologists and to present information on the validity of the NAMCS data by comparing key features of the dermatologist sample to other surveys of dermatologists.