The educational attainment metric is one of many that factor into the overall Best States rankings. See the Best States methodology for a detailed look at the data behind the analysis.

Barro and Lee (2010), for example, constructed measures of educational attainment of the adult population for 146 countries at five-year intervals from 1950 to 2010—broken down by sex and age group.

The number of educational opportunities that children accrue as they mature is strongly linked to their educational attainment and earnings in early adulthood, according to new research led by ...