349 – Health, Hospital, and Patient Surveys
Redesign of the National Ambulatory Medical Care Survey to Support State Estimates
Esther Hing
National Center for Health Statistics
Iris Shimizu
National Center for Health Statistics
The National Ambulatory Medical Care Survey (NAMCS) is an annual nationally representative sample survey of visits to about 3,000 office-based physicians, excluding anesthesiologist, radiologists, and pathologists, and 104 community health centers (CHCs). Prior to 2012, the NAMCS sample design utilized a multistage probability design involving samples of geographic primary sampling units (PSUs), physicians/CHCs within PSUs, providers within CHCs, and visits within provider practices. The survey was not designed to be representative by state and estimates by state were often unreliable. The 2012 NAMCS was redesigned to provide data according to geography, specifically Census division level estimates as well as state-level estimates for as many states as possible. The 2012 NAMCS will provide for the first time state-level estimates for 34 states with the largest populations. The redesigned sample is stratified by state and selects physicians and CHC service sites at the state level at the first stage of sampling. The total sample size is increased to 15,740 physicians and 2,008 CHC sites. Data collection procedures were changed from paper and pencil to computer-assisted data collection. This paper discusses the reasons for the redesign and describes these changes in detail.
