Most of the primary and secondary education in the UEE is done through computer programs like Empiric Education's Glass. Only in fully settled planets there is access to normative schools. Despite the UEE granting a right to public education, the teacher-to-student ratio in public schools is atrocious and only private and military schools offer a more agreeable ratio. Students usually finish their Equivalency between age 17 and 18.
Passing the Equivalency exam is a requirement for military service or university entrance and shouldn't be confused with citizenship.
The reason for the creation of the Equivalency was that, despite Secondary Education becoming the bare minimum mandatory public education level on the United Nations of Earth (UNE), the expansion through the stars made impossible to maintain a normative school system, as children at the frontier were isolated or the teacher-to-student ratio made the task of schooling them difficult.
In the Writer's Guide Equivalency was described as comparable to "high school education."