Source: U.S. Census Bureau
Release: Educational Attainment
Estimate of educational attainment for population 18 years old and over whose highest degree was a master's, or professional or doctorate degree (ACS variable S1501_C02_013E from table S1501).
For more information about the subject definitions, see the ACS technical documentation.
Data for 2020 are based on the experimental estimates from the 1-year American Community Survey released by the Census Bureau instead of the traditional 1-year estimates. For more information, visit the 2020 ACS 1-Year Experimental Data Release page.
Single-year estimates from the American Community Survey (ACS) are "period" estimates derived from a data sample collected over a period of time, as opposed to "point-in-time" estimates such as those from past decennial censuses. ACS single-year estimates include data collected over a 12-month period; explicitly the calendar year (e.g., the 2015 ACS covers the period from January 2015 through December 2015).
Please see the ACS handbook (Section 3, "Understanding and Using ACS Single-Year and Multiyear Estimates" p. 13) for a comprehensive set of details and clarifications.
U.S. Census Bureau, People 25 Years and Over Who Have Completed a Graduate or Professional Degree for Illinois [GCT1503IL], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/GCT1503IL, October 6, 2022.