This study compared estimates of nurse practitioner (NP)
supply in 12 states (statewide and rural vs. urban)
derived from two sources: state license records and
National Provider Identifier (NPI) data. Estimates of
state NP supply from license data were found to be higher
than NPI-derived estimates for most, but not all states.
While data from both license and NPI sources can be
useful for health workforce planning, the limitations of
each source should be acknowledged and workforce
comparisons should be limited to estimates derived from
the same types of data.