Several approaches to defining educational categories are used in Health, United States. Estimates are typically presented for adults aged 25 and over to allow for completion of education.
National Health Interview Survey (NHIS)
Starting in 1997, the NHIS questionnaire was changed to ask, “What is the highest level of school [person] has completed or the highest degree received?” Responses are used to categorize adults according to educational credentials (that is, no high school diploma or GED; high school diploma or GED; some college, no degree; associate’s degree; or bachelor’s degree or higher).
Before 1997, the education variable in NHIS was measured by asking, “What is the highest grade or year of regular school [person] has ever attended?” and “Did [person] finish the grade/year?” Responses were used to categorize adults according to years of education completed (that is, less than 12, 12, 13–15, or 16 years or more).
Data from the 1996 and 1997 NHIS were used to compare distributions of educational attainment for adults aged 25 and over, using categories based on educational credentials (1997) and categories based on years of education completed (1996). A larger percentage of people reported some college than reported 13–15 years of education, and a correspondingly smaller percentage reported a high school diploma or GED than reported 12 years of education. In 1996, 18% of adults reported less than 12 years of education, 37% reported 12 years, 20% reported 13–15 years, and 25% reported 16 or more years of education. In 1997, 19% of adults reported no high school diploma, 31% reported a high school diploma or GED, 26% reported some college, and 24% reported a bachelor’s degree or higher.