Collectively known as midlevel providers, nurse practitioners, physician assistants and nurse midwives can diagnose and treat routine health problems as well as prescribe medicine in most states. Medical groups increasingly view MLPs as key to surviving in the managed-care era. With capitation comes more primary-care visits, particularly those related to prevention, and MLPs are qualified to handle most of them. In addition, groups can improve access by offering some patients the option of seeing an MLP immediately instead of waiting for an appointment with the doctor.