The CNMPPI can be used to document changes in practice authority of CNMs. The increase in state CNMPPI scores and decrease in variance across states can be interpreted as indicating growth of professional authority and increasing consensus regarding the CNM role. The scoring system needs to be updated to reflect the current health systems environment and to include certified midwives and other midwives meeting the International Confederation of Midwives definition of a midwife. Applications of the CNMPPI to future research are discussed.