The term APP refers to physician assistants (PA) and nurse practitioners (NP). Their goal was to assess independent ED APP practice, to the degree possible using billing data. They identified Medicare fee-for-service claims where an APP billed ED professional services under their National Provider Identifier (NPI) number and a physician did not. They compared rural areas, where it is more difficult to hire ED physicians, to urban areas, where it is presumably easier. In 2013, APP-only Medicare ED visits were higher in rural than urban areas: 7% versus 5% of visits. By 2019, rural APP-only visits grew to 15%; urban was 9%. They also quantified APP-only high-acuity visits using Evaluation and Management codes 99285 and 99291. High-acuity APP-only visits increased from 23% in 2013 to 36% in 2019. They concluded that further work is needed "evaluating emergency care staffing decision making." ED care is complicated and nuanced, commonly requiring specific, time-sensitive clinical actions. This