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at least 10 minutes duration and about how long these
sessions generally last. All questions related to leisure-time
physical activity were phrased in terms of current behavior
and lack a specific reference period. Vigorous physical
activity is described as causing heavy sweating or a large
increase in breathing or heart rate, and light/moderate as
causing light sweating or a slight to moderate increase in
breathing or heart rate. Adults were also asked about how
often they did leisure-time physical activities specifically
designed to strengthen their muscles, such as lifting weights
or doing calisthenics. For more information, see the
NHIS Adult Physical Activity Information website at:
http://www.cdc.gov/nchs/nhis/physical_activity.htm.
Physician—Data on physician characteristics are obtained
through physician self-report from the American Medical
Association's (AMA) Physician Masterfile. Although the AMA
collects data for both doctors of medicine (MDs) and doctors
of osteopathy (DOs), in Health, United States data for DOs
come from the American Osteopathic Association.
Active (or professionally active) physician—These
physicians are currently engaged in patient care or other
professional activity for a minimum of 20 hours per week.
Other professional activity includes administration,
medical teaching, research, and other activities such as
employment with insurance carriers, pharmaceutical
companies, corporations, voluntary organizations, and
medical societies. Physicians who are retired, semiretired,
working part-time, or not practicing are classified as
inactive and are excluded. Also excluded are physicians
with unknown address and physicians who did not
provide information on type of practice or present
employment (not classified).
Hospital-based physician—These physicians are
employed under contract with hospitals to provide direct
patient care and include physicians in residency training
(including clinical fellows) and full-time members of the
hospital staff.
Office-based physician—These physicians are engaged in
seeing patients in solo practice, group practice, twophysician
practice, other patient care employment, or in
providing inpatient services such as those offered by
pathologists and radiologists.
Data for physicians are presented by type of education
(doctor of medicine or doctor of osteopathy); place of
education (U.S. medical graduates and international
medical graduates); activity status (professionally active
and inactive); area of specialty; and geographic area.
(Also see Appendix II, Physician specialty.)
Physician specialty—A physician specialty is any specific
branch of medicine in which a physician may concentrate.
Data are based on physician self-reports of their primary
area of specialty. Physician data are broadly categorized into
two areas of practice: those who provide primary care and
those who provide specialty care.
Primary care generalist—These physicians practice in the
general fields of family medicine, general practice,
internal medicine, obstetrics and gynecology, and
pediatrics. Specifically excluded are primary care
specialists associated with these generalist fields.
Primary care specialist—These specialists practice in the
primary care subspecialties of family medicine, internal
medicine, obstetrics and gynecology, and pediatrics.
Family medicine subspecialties include geriatric
medicine and sports medicine. Internal medicine
subspecialties include adolescent medicine, critical care
medicine, diabetes, endocrinology, diabetes and
metabolism, hematology, hepatology, hematology/
oncology, cardiac electrophysiology, infectious diseases,
clinical and laboratory immunology, geriatric medicine,
sports medicine, nephrology, nutrition, medical
oncology, pulmonary critical care medicine, and
rheumatology. Obstetrics and gynecology subspecialties
include hospice and palliative medicine (obstetrics and
gynecology), maternal and fetal medicine, critical care
medicine (obstetrics and gynecology), and reproductive
endocrinology. Pediatric subspecialties include
adolescent medicine, pediatric critical care medicine,
pediatrics/internal medicine, neonatal–perinatal
medicine, pediatric allergy, pediatric cardiology, pediatric
endocrinology, pediatric infectious disease, pediatric
pulmonology, medical toxicology (pediatrics), pediatric
emergency medicine, pediatric gastroenterology,
pediatric hematology/oncology, clinical and laboratory
immunology (pediatrics), pediatric nephrology, pediatric
rheumatology, and sports medicine (pediatrics).
Specialty care physician—These physicians are sometimes
called specialists and include primary care specialists
listed above in addition to all other physicians not
included in the generalist definition. Specialty fields
include allergy and immunology, aerospace medicine,
anesthesiology, cardiovascular diseases, child and
adolescent psychiatry, colon and rectal surgery,
dermatology, diagnostic radiology, forensic pathology,
gastroenterology, general surgery, medical genetics,
neurology, nuclear medicine, neurological surgery,
occupational medicine, ophthalmology, orthopedic
surgery, otolaryngology, psychiatry, public health and
general preventive medicine, physical medicine and
rehabilitation, plastic surgery, anatomic and clinical
pathology, pulmonary diseases, radiation oncology,
thoracic surgery, urology, addiction medicine, critical
care medicine, legal medicine, and clinical
pharmacology.
(Also see Appendix II, Physician.)
Population—The U.S. Census Bureau collects and publishes
data on populations in the United States according to
several different definitions. Various statistical systems then
use the appropriate population for calculating rates. (Also
434 Appendix II. Definitions and Methods Health, United States, 2014