“…However, the "phenotype" educational attainment has been operationally defined in many different ways, such as years of education (Okbay et al, 2016), highest degree completed (Belsky et al, 2016), and score on a U.K. nationwide examination (Rimfeld et al, 2015;Shakeshaft et al, 2013). It is also possible to study the link between genetics and certain components of education attainment such as mathematics (Chen et al, 2017;Wang et al, 2014) or reading (Christopher et al, 2016;Davis et al, 2014;Gialluisi, Guadalupe, Francks, & Fisher, 2016). It is unclear whether these different measurements of educational attainment are all tapping into the same phenotype, or instead measuring distinct components of behavior.…”